diff --git a/docs/building-extensions/plugins/plugin-events/index.md b/docs/building-extensions/plugins/plugin-events/index.md
index 19f3ddec..d12f2f17 100644
--- a/docs/building-extensions/plugins/plugin-events/index.md
+++ b/docs/building-extensions/plugins/plugin-events/index.md
@@ -29,6 +29,10 @@ The event Group refers to the group of plugins which Joomla ensures are imported
 | [onContentBeforeChangeState](./content.md#oncontentbeforechangestate) | In Model, before a set of records changes state | Content      |  4.0  |
 | [onContentChangeState](./content.md#oncontentchangestate) | In Model, after a set of records changes state | Content          |  before 4.0  |
 | [onCategoryChangeState](./content.md#oncategorychangestate) | In Model, before a set of category records changes state | Content     |  before 4.0  |
+| [onInstallerAddInstallationTab](./installer.md#oninstalleraddinstallationtab) | In com_installer, in building the Install / Extensions form | Installer     |  before 4.0  |
 | [onInstallerBeforePackageDownload](./installer.md#oninstallerbeforepackagedownload) | In Installer, before a package is downloaded | Installer     |  before 4.0  |
 | [onInstallerBeforeUpdateSiteDownload](./installer.md#oninstallerbeforeupdatesitedownload) | In Installer, before an update site is downloaded | Installer     |  5.3  |
+| [onInstallerBeforeInstallation](./installer.md#oninstallerbeforeinstallation) | At the beginning of the installation of a package / extension | Installer     |  before 4.0  |
+| [onInstallerBeforeInstaller](./installer.md#oninstallerbeforeinstaller) | After zip files extracted, before extension installation | Installer     |  before 4.0  |
+| [onInstallerAfterInstaller](./installer.md#oninstallerafterinstaller) | After extension installation | Installer     |  before 4.0  |
 
diff --git a/docs/building-extensions/plugins/plugin-events/installer.md b/docs/building-extensions/plugins/plugin-events/installer.md
index cd48f9ff..4a1728c5 100644
--- a/docs/building-extensions/plugins/plugin-events/installer.md
+++ b/docs/building-extensions/plugins/plugin-events/installer.md
@@ -10,6 +10,32 @@ Installer Events
 
 Installer plugin events are triggered when some routines are performed during the install process of extensions or when their update sites are downloaded.
 
+For an overview of how a number of these events fit into the installation process see [Install Process](../../install-update/installation/install-process.md).
+(Note that the onExtensionBeforeInstall and onExtensionAfterInstall events aren't covered here).
+
+For background on Joomla transitioning to using classes for events see [Joomla 4 and 5 changes](../joomla-4-and-5-changes.md), 
+where you can also find explanations for [accessing the arguments](../joomla-4-and-5-changes.md#summary---accessing-event-arguments) 
+and [returning values](../joomla-4-and-5-changes.md#summary---returning-values). 
+
+## onInstallerAddInstallationTab
+
+### Description
+
+This event is triggered when Joomla is building the form in the administrator Install / Extensions page.
+
+### Event Arguments
+
+The event class `\Joomla\CMS\Event\Installer\AddInstallationTabEvent` has no arguments.
+
+### Return Value
+
+Return the contents of the additional tab which you want to include in the options for install.
+
+### Examples
+
+The Joomla core uses this mechanism to create the tabs "Upload Package File", "Install from Folder" etc. 
+You should look at these install plugins and follow them as exemplars. 
+
 ## onInstallerBeforePackageDownload
 
 ### Description
@@ -66,3 +92,134 @@ public function onInstallerBeforeUpdateSiteDownload(\Joomla\CMS\Event\Installer\
     $event->updateUrl($event->getUrl() . '?auth=foo');
 }
 ```
+
+## onInstallerBeforeInstallation
+
+### Description
+
+This event is triggered at the beginning of an installation operation. 
+
+### Event Arguments
+
+The event class `\Joomla\CMS\Event\Installer\BeforeInstallationEvent` has the following arguments:
+
+- **`subject`** - This will be the FQN of the install model class Joomla\Component\Installer\Administrator\Model\InstallModel
+
+Note that there is no getter for the subject argument. Instead you should use:
+
+```php
+public function onInstallerBeforeInstallation(\Joomla\CMS\Event\Installer\BeforeInstallationEvent $event): void
+{
+    $args = $event->getArguments();
+    $subject = $args['subject'];
+}
+```
+
+- **`package`** - This is null. 
+
+### Return Value
+
+A return value of true will cause the Joomla installer to exit with true (indicating that the extension was installed).
+
+A return value of false will cause the Joomla installer to exit with false (indicating that the extension installation failed).
+
+If you don't set a return value then the installation will continue as normal. 
+
+You can also set the package as described for the event onInstallerBeforeInstaller below.
+
+## onInstallerBeforeInstaller
+
+### Description
+
+This event is triggered after the extension code has been obtained, and any extraction of zip files performed,
+but before Joomla has started to process the extension's installation files. 
+
+### Event Arguments
+
+The event class `\Joomla\CMS\Event\Installer\BeforeInstallerEvent` has the following arguments:
+
+- **`subject`** - This will be the FQN of the install model class Joomla\Component\Installer\Administrator\Model\InstallModel
+
+Note that there is no getter for the subject argument. Instead you should use:
+
+```php
+public function onInstallerBeforeInstaller(\Joomla\CMS\Event\Installer\BeforeInstallerEvent $event): void
+{
+    $args = $event->getArguments();
+    $subject = $args['subject'];
+}
+```
+
+- **`package`** - This is an array of 4 elements, which in the case of uploading a zip file will contain:
+ 
+   - extractdir - the directory into which the zip file has been extracted
+   - packagefile - the location of the zip file
+   - dir - the directory containing the extension manifest file, and the other installation files
+   - type - the type of extension (eg "plugin")
+
+The array elements vary depending upon how the installation code is selected. 
+For example, for "Install from Folder" the extractdir and packagefile elements will be null.
+
+### Return Value
+
+A return value of true will cause the Joomla installer to exit with true (indicating that the extension was installed).
+
+A return value of false will cause the Joomla installer to exit with false (indicating that the extension installation failed).
+
+If you don't set a return value then the installation will continue as normal. 
+
+You can also set the package to be installed, overriding what the administrator selected, eg:
+
+```php
+public function onInstallerBeforeInstaller(\Joomla\CMS\Event\Installer\BeforeInstallerEvent $event): void
+{
+    $newpkg = array("dir" => $pathToExtensionDirectory, "type" => "plugin", "extractdir" => null, "packagefile" => null);
+    $event->updatePackage($newpkg);
+}
+```
+
+## onInstallerAfterInstaller
+
+### Description
+
+This event is triggered after extension has been installed. 
+
+### Event Arguments
+
+The event class `\Joomla\CMS\Event\Installer\AfterInstallerEvent` has the following arguments:
+
+- **`subject`** - This will be the FQN of the install model class Joomla\Component\Installer\Administrator\Model\InstallModel
+
+Note that there is no getter for the subject argument. Instead you should use:
+
+```php
+public function onInstallerAfterInstaller(\Joomla\CMS\Event\Installer\AfterInstallerEvent $event): void
+{
+    $args = $event->getArguments();
+    $subject = $args['subject'];
+}
+```
+
+- **`package`** - The package which has been installed, in the form described in onInstallerBeforeInstaller above.
+
+- **`installer`** - The installer class - Joomla sets this to "Joomla\CMS\Installer\Installer"
+
+- **`installerResult`** - true or false, depending upon whether the package was successfully installed or not 
+
+- **`message`** - The message output to the administrator, eg "Installation of the plugin was successful."
+
+### Return Value
+
+You can set the installer result and message, eg:
+
+```php
+public function onInstallerAfterInstaller(\Joomla\CMS\Event\Installer\AfterInstallerEvent $event): void
+{
+    $event->updateInstallerResult(false);
+    $event->updateMessage("Some failure message");
+}
+```
+
+However, at this stage the installation has been completed, so setting the installer result in this way has little impact.
+
+If you set the message then it is output instead of the standard Joomla message.
\ No newline at end of file
diff --git a/versioned_docs/version-4.4/building-extensions/plugins/plugin-events/index.md b/versioned_docs/version-4.4/building-extensions/plugins/plugin-events/index.md
index a17e7d7d..8ba5d089 100644
--- a/versioned_docs/version-4.4/building-extensions/plugins/plugin-events/index.md
+++ b/versioned_docs/version-4.4/building-extensions/plugins/plugin-events/index.md
@@ -29,4 +29,9 @@ The event Group refers to the group of plugins which Joomla ensures are imported
 | [onContentBeforeChangeState](./content.md#oncontentbeforechangestate) | In Model, before a set of records changes state | Content      |  4.0  |
 | [onContentChangeState](./content.md#oncontentchangestate) | In Model, after a set of records changes state | Content          |  before 4.0  |
 | [onCategoryChangeState](./content.md#oncategorychangestate) | In Model, before a set of category records changes state | Content     |  before 4.0  |
+| [onInstallerAddInstallationTab](./installer.md#oninstalleraddinstallationtab) | In com_installer, in building the Install / Extensions form | Installer     |  before 4.0  |
 | [onInstallerBeforePackageDownload](./installer.md#oninstallerbeforepackagedownload) | In Installer, before a package is downloaded | Installer     |  before 4.0  |
+| [onInstallerBeforeInstallation](./installer.md#oninstallerbeforeinstallation) | At the beginning of the installation of a package / extension | Installer     |  before 4.0  |
+| [onInstallerBeforeInstaller](./installer.md#oninstallerbeforeinstaller) | After zip files extracted, before extension installation | Installer     |  before 4.0  |
+| [onInstallerAfterInstaller](./installer.md#oninstallerafterinstaller) | After extension installation | Installer     |  before 4.0  |
+
diff --git a/versioned_docs/version-4.4/building-extensions/plugins/plugin-events/installer.md b/versioned_docs/version-4.4/building-extensions/plugins/plugin-events/installer.md
index ed7dd2f4..45449602 100644
--- a/versioned_docs/version-4.4/building-extensions/plugins/plugin-events/installer.md
+++ b/versioned_docs/version-4.4/building-extensions/plugins/plugin-events/installer.md
@@ -10,6 +10,32 @@ Installer Events
 
 Installer plugin events are triggered when some routines are performed during the install process of extensions or when their update sites are downloaded.
 
+For an overview of how a number of these events fit into the installation process see [Install Process](../../install-update/installation/install-process.md).
+(Note that the onExtensionBeforeInstall and onExtensionAfterInstall events aren't covered here).
+
+For background on Joomla transitioning to using classes for events see [Joomla 4 and 5 changes](../joomla-4-and-5-changes.md), 
+where you can also find explanations for [accessing the arguments](../joomla-4-and-5-changes.md#summary---accessing-event-arguments) 
+and [returning values](../joomla-4-and-5-changes.md#summary---returning-values). 
+
+## onInstallerAddInstallationTab
+
+### Description
+
+This event is triggered when Joomla is building the form in the administrator Install / Extensions page.
+
+### Event Arguments
+
+The event class `\Joomla\CMS\Event\Installer\AddInstallationTabEvent` has no arguments.
+
+### Return Value
+
+Return the contents of the additional tab which you want to include in the options for install.
+
+### Examples
+
+The Joomla core uses this mechanism to create the tabs "Upload Package File", "Install from Folder" etc. 
+You should look at these install plugins and follow them as exemplars. 
+
 ## onInstallerBeforePackageDownload
 
 ### Description
@@ -19,7 +45,7 @@ This event will be executed before an installable package (zip file) of an exten
 
 ### Event Arguments
 
-The event class  `\Joomla\CMS\Event\Installer\BeforePackageDownloadEvent` has the following arguments:
+The event class `\Joomla\CMS\Event\Installer\BeforePackageDownloadEvent` has the following arguments:
 
 
 - **`url`** - The url of the package.
@@ -39,3 +65,118 @@ public function onInstallerBeforePackageDownload(\Joomla\CMS\Event\Installer\Bef
 }
 ```
 
+## onInstallerBeforeInstallation
+
+### Description
+
+This event is triggered at the beginning of an installation operation. 
+
+### Event Arguments
+
+The event class `\Joomla\CMS\Event\Installer\BeforeInstallationEvent` has the following arguments:
+
+- **`subject`** - This will be the FQN of the install model class Joomla\Component\Installer\Administrator\Model\InstallModel
+
+Note that there is no getter for the subject argument. Instead you should use:
+
+```php
+public function onInstallerBeforeInstallation(\Joomla\CMS\Event\Installer\BeforeInstallationEvent $event): void
+{
+    $args = $event->getArguments();
+    $subject = $args['subject'];
+}
+```
+
+- **`package`** - This is null. 
+
+The **`package`** is passed by reference, so you can update it, but this approach is deprecated 
+and you should view the documentation for more up-to-date versions to understand what will change. 
+
+### Return Value
+
+A return value of true will cause the Joomla installer to exit with true (indicating that the extension was installed).
+
+A return value of false will cause the Joomla installer to exit with false (indicating that the extension installation failed).
+
+If you don't set a return value then the installation will continue as normal. 
+
+## onInstallerBeforeInstaller
+
+### Description
+
+This event is triggered after the extension code has been obtained, and any extraction of zip files performed,
+but before Joomla has started to process the extension's installation files. 
+
+### Event Arguments
+
+The event class `\Joomla\CMS\Event\Installer\BeforeInstallerEvent` has the following arguments:
+
+- **`subject`** - This will be the FQN of the install model class Joomla\Component\Installer\Administrator\Model\InstallModel
+
+Note that there is no getter for the subject argument. Instead you should use:
+
+```php
+public function onInstallerBeforeInstaller(\Joomla\CMS\Event\Installer\BeforeInstallerEvent $event): void
+{
+    $args = $event->getArguments();
+    $subject = $args['subject'];
+}
+```
+
+- **`package`** - This is an array of 4 elements, which in the case of uploading a zip file will contain:
+ 
+   - extractdir - the directory into which the zip file has been extracted
+   - packagefile - the location of the zip file
+   - dir - the directory containing the extension manifest file, and the other installation files
+   - type - the type of extension (eg "plugin")
+
+The array elements vary depending upon how the installation code is selected. 
+For example, for "Install from Folder" the extractdir and packagefile elements will be null.
+
+The **`package`** is passed by reference, so you can update it, but this approach is deprecated 
+and you should view the documentation for more up-to-date versions to understand what will change. 
+
+### Return Value
+
+A return value of true will cause the Joomla installer to exit with true (indicating that the extension was installed).
+
+A return value of false will cause the Joomla installer to exit with false (indicating that the extension installation failed).
+
+If you don't set a return value then the installation will continue as normal. 
+
+## onInstallerAfterInstaller
+
+### Description
+
+This event is triggered after extension has been installed. 
+
+### Event Arguments
+
+The event class `\Joomla\CMS\Event\Installer\AfterInstallerEvent` has the following arguments:
+
+- **`subject`** - This will be the FQN of the install model class Joomla\Component\Installer\Administrator\Model\InstallModel
+
+Note that there is no getter for the subject argument. Instead you should use:
+
+```php
+public function onInstallerAfterInstaller(\Joomla\CMS\Event\Installer\AfterInstallerEvent $event): void
+{
+    $args = $event->getArguments();
+    $subject = $args['subject'];
+}
+```
+
+- **`package`** - The package which has been installed, in the form described in onInstallerBeforeInstaller above.
+
+- **`installer`** - The installer class - Joomla sets this to "Joomla\CMS\Installer\Installer"
+
+- **`installerResult`** - true or false, depending upon whether the package was successfully installed or not 
+
+- **`message`** - The message output to the administrator, eg "Installation of the plugin was successful."
+
+### Return Value
+
+Any return value has limited affect, as the extension has already been installed at this stage.
+
+The **`installerResult`** and **`message`** are passed by reference, so you can update them, but this approach is deprecated 
+and you should view the documentation for more up-to-date versions to understand what will change. 
\ No newline at end of file
diff --git a/versioned_docs/version-5.4/building-extensions/plugins/plugin-events/index.md b/versioned_docs/version-5.4/building-extensions/plugins/plugin-events/index.md
index 063635f6..f2719a34 100644
--- a/versioned_docs/version-5.4/building-extensions/plugins/plugin-events/index.md
+++ b/versioned_docs/version-5.4/building-extensions/plugins/plugin-events/index.md
@@ -29,6 +29,10 @@ The event Group refers to the group of plugins which Joomla ensures are imported
 | [onContentBeforeChangeState](./content.md#oncontentbeforechangestate) | In Model, before a set of records changes state | Content      |  4.0  |
 | [onContentChangeState](./content.md#oncontentchangestate) | In Model, after a set of records changes state | Content          |  before 4.0  |
 | [onCategoryChangeState](./content.md#oncategorychangestate) | In Model, before a set of category records changes state | Content     |  before 4.0  |
+| [onInstallerAddInstallationTab](./installer.md#oninstalleraddinstallationtab) | In com_installer, in building the Install / Extensions form | Installer     |  before 4.0  |
 | [onInstallerBeforePackageDownload](./installer.md#oninstallerbeforepackagedownload) | In Installer, before a package is downloaded | Installer     |  before 4.0  |
 | [onInstallerBeforeUpdateSiteDownload](./installer.md#oninstallerbeforeupdatesitedownload) | In Installer, before an update site is downloaded | Installer     |  5.3  |
+| [onInstallerBeforeInstallation](./installer.md#oninstallerbeforeinstallation) | At the beginning of the installation of a package / extension | Installer     |  before 4.0  |
+| [onInstallerBeforeInstaller](./installer.md#oninstallerbeforeinstaller) | After zip files extracted, before extension installation | Installer     |  before 4.0  |
+| [onInstallerAfterInstaller](./installer.md#oninstallerafterinstaller) | After extension installation | Installer     |  before 4.0  |
 
diff --git a/versioned_docs/version-5.4/building-extensions/plugins/plugin-events/installer.md b/versioned_docs/version-5.4/building-extensions/plugins/plugin-events/installer.md
index 92bef3a5..9fbdf84d 100644
--- a/versioned_docs/version-5.4/building-extensions/plugins/plugin-events/installer.md
+++ b/versioned_docs/version-5.4/building-extensions/plugins/plugin-events/installer.md
@@ -10,6 +10,32 @@ Installer Events
 
 Installer plugin events are triggered when some routines are performed during the install process of extensions or when their update sites are downloaded.
 
+For an overview of how a number of these events fit into the installation process see [Install Process](../../install-update/installation/install-process.md).
+(Note that the onExtensionBeforeInstall and onExtensionAfterInstall events aren't covered here).
+
+For background on Joomla transitioning to using classes for events see [Joomla 4 and 5 changes](../joomla-4-and-5-changes.md), 
+where you can also find explanations for [accessing the arguments](../joomla-4-and-5-changes.md#summary---accessing-event-arguments) 
+and [returning values](../joomla-4-and-5-changes.md#summary---returning-values). 
+
+## onInstallerAddInstallationTab
+
+### Description
+
+This event is triggered when Joomla is building the form in the administrator Install / Extensions page.
+
+### Event Arguments
+
+The event class `\Joomla\CMS\Event\Installer\AddInstallationTabEvent` has no arguments.
+
+### Return Value
+
+Return the contents of the additional tab which you want to include in the options for install.
+
+### Examples
+
+The Joomla core uses this mechanism to create the tabs "Upload Package File", "Install from Folder" etc. 
+You should look at these install plugins and follow them as exemplars. 
+
 ## onInstallerBeforePackageDownload
 
 ### Description
@@ -66,3 +92,134 @@ public function onInstallerBeforeUpdateSiteDownload(\Joomla\CMS\Event\Installer\
     $event->updateUrl($event->getUrl() . '?auth=foo');
 }
 ```
+
+## onInstallerBeforeInstallation
+
+### Description
+
+This event is triggered at the beginning of an installation operation. 
+
+### Event Arguments
+
+The event class `\Joomla\CMS\Event\Installer\BeforeInstallationEvent` has the following arguments:
+
+- **`subject`** - This will be the FQN of the install model class Joomla\Component\Installer\Administrator\Model\InstallModel
+
+Note that there is no getter for the subject argument. Instead you should use:
+
+```php
+public function onInstallerBeforeInstallation(\Joomla\CMS\Event\Installer\BeforeInstallationEvent $event): void
+{
+    $args = $event->getArguments();
+    $subject = $args['subject'];
+}
+```
+
+- **`package`** - This is null. 
+
+### Return Value
+
+A return value of true will cause the Joomla installer to exit with true (indicating that the extension was installed).
+
+A return value of false will cause the Joomla installer to exit with false (indicating that the extension installation failed).
+
+If you don't set a return value then the installation will continue as normal. 
+
+You can also set the package as described for the event onInstallerBeforeInstaller below.
+
+## onInstallerBeforeInstaller
+
+### Description
+
+This event is triggered after the extension code has been obtained, and any extraction of zip files performed,
+but before Joomla has started to process the extension's installation files. 
+
+### Event Arguments
+
+The event class `\Joomla\CMS\Event\Installer\BeforeInstallerEvent` has the following arguments:
+
+- **`subject`** - This will be the FQN of the install model class Joomla\Component\Installer\Administrator\Model\InstallModel
+
+Note that there is no getter for the subject argument. Instead you should use:
+
+```php
+public function onInstallerBeforeInstaller(\Joomla\CMS\Event\Installer\BeforeInstallerEvent $event): void
+{
+    $args = $event->getArguments();
+    $subject = $args['subject'];
+}
+```
+
+- **`package`** - This is an array of 4 elements, which in the case of uploading a zip file will contain:
+ 
+   - extractdir - the directory into which the zip file has been extracted
+   - packagefile - the location of the zip file
+   - dir - the directory containing the extension manifest file, and the other installation files
+   - type - the type of extension (eg "plugin")
+
+The array elements vary depending upon how the installation code is selected. 
+For example, for "Install from Folder" the extractdir and packagefile elements will be null.
+
+### Return Value
+
+A return value of true will cause the Joomla installer to exit with true (indicating that the extension was installed).
+
+A return value of false will cause the Joomla installer to exit with false (indicating that the extension installation failed).
+
+If you don't set a return value then the installation will continue as normal. 
+
+You can also set the package to be installed, overriding what the administrator selected, eg:
+
+```php
+public function onInstallerBeforeInstaller(\Joomla\CMS\Event\Installer\BeforeInstallerEvent $event): void
+{
+    $newpkg = array("dir" => $pathToExtensionDirectory, "type" => "plugin", "extractdir" => null, "packagefile" => null);
+    $event->updatePackage($newpkg);
+}
+```
+
+## onInstallerAfterInstaller
+
+### Description
+
+This event is triggered after extension has been installed. 
+
+### Event Arguments
+
+The event class `\Joomla\CMS\Event\Installer\AfterInstallerEvent` has the following arguments:
+
+- **`subject`** - This will be the FQN of the install model class Joomla\Component\Installer\Administrator\Model\InstallModel
+
+Note that there is no getter for the subject argument. Instead you should use:
+
+```php
+public function onInstallerAfterInstaller(\Joomla\CMS\Event\Installer\AfterInstallerEvent $event): void
+{
+    $args = $event->getArguments();
+    $subject = $args['subject'];
+}
+```
+
+- **`package`** - The package which has been installed, in the form described in onInstallerBeforeInstaller above.
+
+- **`installer`** - The installer class - Joomla sets this to "Joomla\CMS\Installer\Installer"
+
+- **`installerResult`** - true or false, depending upon whether the package was successfully installed or not 
+
+- **`message`** - The message output to the administrator, eg "Installation of the plugin was successful."
+
+### Return Value
+
+You can set the installer result and message, eg:
+
+```php
+public function onInstallerAfterInstaller(\Joomla\CMS\Event\Installer\AfterInstallerEvent $event): void
+{
+    $event->updateInstallerResult(false);
+    $event->updateMessage("Some failure message");
+}
+```
+
+However, at this stage the installation has been completed, so setting the installer result in this way has little impact.
+
+If you set the message then it is output instead of the standard Joomla message.
\ No newline at end of file
diff --git a/versioned_docs/version-6.0/building-extensions/plugins/plugin-events/index.md b/versioned_docs/version-6.0/building-extensions/plugins/plugin-events/index.md
index 063635f6..f2719a34 100644
--- a/versioned_docs/version-6.0/building-extensions/plugins/plugin-events/index.md
+++ b/versioned_docs/version-6.0/building-extensions/plugins/plugin-events/index.md
@@ -29,6 +29,10 @@ The event Group refers to the group of plugins which Joomla ensures are imported
 | [onContentBeforeChangeState](./content.md#oncontentbeforechangestate) | In Model, before a set of records changes state | Content      |  4.0  |
 | [onContentChangeState](./content.md#oncontentchangestate) | In Model, after a set of records changes state | Content          |  before 4.0  |
 | [onCategoryChangeState](./content.md#oncategorychangestate) | In Model, before a set of category records changes state | Content     |  before 4.0  |
+| [onInstallerAddInstallationTab](./installer.md#oninstalleraddinstallationtab) | In com_installer, in building the Install / Extensions form | Installer     |  before 4.0  |
 | [onInstallerBeforePackageDownload](./installer.md#oninstallerbeforepackagedownload) | In Installer, before a package is downloaded | Installer     |  before 4.0  |
 | [onInstallerBeforeUpdateSiteDownload](./installer.md#oninstallerbeforeupdatesitedownload) | In Installer, before an update site is downloaded | Installer     |  5.3  |
+| [onInstallerBeforeInstallation](./installer.md#oninstallerbeforeinstallation) | At the beginning of the installation of a package / extension | Installer     |  before 4.0  |
+| [onInstallerBeforeInstaller](./installer.md#oninstallerbeforeinstaller) | After zip files extracted, before extension installation | Installer     |  before 4.0  |
+| [onInstallerAfterInstaller](./installer.md#oninstallerafterinstaller) | After extension installation | Installer     |  before 4.0  |
 
diff --git a/versioned_docs/version-6.0/building-extensions/plugins/plugin-events/installer.md b/versioned_docs/version-6.0/building-extensions/plugins/plugin-events/installer.md
index 92bef3a5..9fbdf84d 100644
--- a/versioned_docs/version-6.0/building-extensions/plugins/plugin-events/installer.md
+++ b/versioned_docs/version-6.0/building-extensions/plugins/plugin-events/installer.md
@@ -10,6 +10,32 @@ Installer Events
 
 Installer plugin events are triggered when some routines are performed during the install process of extensions or when their update sites are downloaded.
 
+For an overview of how a number of these events fit into the installation process see [Install Process](../../install-update/installation/install-process.md).
+(Note that the onExtensionBeforeInstall and onExtensionAfterInstall events aren't covered here).
+
+For background on Joomla transitioning to using classes for events see [Joomla 4 and 5 changes](../joomla-4-and-5-changes.md), 
+where you can also find explanations for [accessing the arguments](../joomla-4-and-5-changes.md#summary---accessing-event-arguments) 
+and [returning values](../joomla-4-and-5-changes.md#summary---returning-values). 
+
+## onInstallerAddInstallationTab
+
+### Description
+
+This event is triggered when Joomla is building the form in the administrator Install / Extensions page.
+
+### Event Arguments
+
+The event class `\Joomla\CMS\Event\Installer\AddInstallationTabEvent` has no arguments.
+
+### Return Value
+
+Return the contents of the additional tab which you want to include in the options for install.
+
+### Examples
+
+The Joomla core uses this mechanism to create the tabs "Upload Package File", "Install from Folder" etc. 
+You should look at these install plugins and follow them as exemplars. 
+
 ## onInstallerBeforePackageDownload
 
 ### Description
@@ -66,3 +92,134 @@ public function onInstallerBeforeUpdateSiteDownload(\Joomla\CMS\Event\Installer\
     $event->updateUrl($event->getUrl() . '?auth=foo');
 }
 ```
+
+## onInstallerBeforeInstallation
+
+### Description
+
+This event is triggered at the beginning of an installation operation. 
+
+### Event Arguments
+
+The event class `\Joomla\CMS\Event\Installer\BeforeInstallationEvent` has the following arguments:
+
+- **`subject`** - This will be the FQN of the install model class Joomla\Component\Installer\Administrator\Model\InstallModel
+
+Note that there is no getter for the subject argument. Instead you should use:
+
+```php
+public function onInstallerBeforeInstallation(\Joomla\CMS\Event\Installer\BeforeInstallationEvent $event): void
+{
+    $args = $event->getArguments();
+    $subject = $args['subject'];
+}
+```
+
+- **`package`** - This is null. 
+
+### Return Value
+
+A return value of true will cause the Joomla installer to exit with true (indicating that the extension was installed).
+
+A return value of false will cause the Joomla installer to exit with false (indicating that the extension installation failed).
+
+If you don't set a return value then the installation will continue as normal. 
+
+You can also set the package as described for the event onInstallerBeforeInstaller below.
+
+## onInstallerBeforeInstaller
+
+### Description
+
+This event is triggered after the extension code has been obtained, and any extraction of zip files performed,
+but before Joomla has started to process the extension's installation files. 
+
+### Event Arguments
+
+The event class `\Joomla\CMS\Event\Installer\BeforeInstallerEvent` has the following arguments:
+
+- **`subject`** - This will be the FQN of the install model class Joomla\Component\Installer\Administrator\Model\InstallModel
+
+Note that there is no getter for the subject argument. Instead you should use:
+
+```php
+public function onInstallerBeforeInstaller(\Joomla\CMS\Event\Installer\BeforeInstallerEvent $event): void
+{
+    $args = $event->getArguments();
+    $subject = $args['subject'];
+}
+```
+
+- **`package`** - This is an array of 4 elements, which in the case of uploading a zip file will contain:
+ 
+   - extractdir - the directory into which the zip file has been extracted
+   - packagefile - the location of the zip file
+   - dir - the directory containing the extension manifest file, and the other installation files
+   - type - the type of extension (eg "plugin")
+
+The array elements vary depending upon how the installation code is selected. 
+For example, for "Install from Folder" the extractdir and packagefile elements will be null.
+
+### Return Value
+
+A return value of true will cause the Joomla installer to exit with true (indicating that the extension was installed).
+
+A return value of false will cause the Joomla installer to exit with false (indicating that the extension installation failed).
+
+If you don't set a return value then the installation will continue as normal. 
+
+You can also set the package to be installed, overriding what the administrator selected, eg:
+
+```php
+public function onInstallerBeforeInstaller(\Joomla\CMS\Event\Installer\BeforeInstallerEvent $event): void
+{
+    $newpkg = array("dir" => $pathToExtensionDirectory, "type" => "plugin", "extractdir" => null, "packagefile" => null);
+    $event->updatePackage($newpkg);
+}
+```
+
+## onInstallerAfterInstaller
+
+### Description
+
+This event is triggered after extension has been installed. 
+
+### Event Arguments
+
+The event class `\Joomla\CMS\Event\Installer\AfterInstallerEvent` has the following arguments:
+
+- **`subject`** - This will be the FQN of the install model class Joomla\Component\Installer\Administrator\Model\InstallModel
+
+Note that there is no getter for the subject argument. Instead you should use:
+
+```php
+public function onInstallerAfterInstaller(\Joomla\CMS\Event\Installer\AfterInstallerEvent $event): void
+{
+    $args = $event->getArguments();
+    $subject = $args['subject'];
+}
+```
+
+- **`package`** - The package which has been installed, in the form described in onInstallerBeforeInstaller above.
+
+- **`installer`** - The installer class - Joomla sets this to "Joomla\CMS\Installer\Installer"
+
+- **`installerResult`** - true or false, depending upon whether the package was successfully installed or not 
+
+- **`message`** - The message output to the administrator, eg "Installation of the plugin was successful."
+
+### Return Value
+
+You can set the installer result and message, eg:
+
+```php
+public function onInstallerAfterInstaller(\Joomla\CMS\Event\Installer\AfterInstallerEvent $event): void
+{
+    $event->updateInstallerResult(false);
+    $event->updateMessage("Some failure message");
+}
+```
+
+However, at this stage the installation has been completed, so setting the installer result in this way has little impact.
+
+If you set the message then it is output instead of the standard Joomla message.
\ No newline at end of file