Add information about building

Documentation/BugfixingAZ/Index.rst

@@ -70,6 +70,9 @@ as described in :ref:`setup <setup>`. Especially the
    For new features, breaking changes and deprecations, it is necessary to :ref:`add
    information to the changelog <changelog>`.
 
+   If you change SCSS, JavaScript or TypeScript files, you can :ref:`build <build>`
+   locally.
+
    Add Unit Tests or Functional Tests for new functionality, refine existing tests
    if necessary. Tests are important because they ensure that
    TYPO3 will behave consistently now and in the future.

Documentation/Build/Index.rst

@@ -0,0 +1,37 @@
+. include:: /Includes.rst.txt
+
+.. highlight:: bash
+
+.. index::
+   single: Code Contribution Workflow; Build
+   single: Build
+   single: SCSS
+   single: TypeScript
+.. _build:
+
+===============
+Building assets
+===============
+
+This page explains building assets like JavaScript and CSS files.
+
+For the most part, the TypeScript, JavaScript and SCSS sources are contained in
+:file:`Build/Sources`. These are compiled to target files, usually located in:
+
+* CSS: :file:`typo3/sysext/*/Resources/Public/Css`
+* JavaScript: :file:`typo3/sysext/*/Resources/Public/JavaScript`
+
+If you make changes to the source files, you can build locally using
+:ref:`runTests.sh <runTests_sh>`:
+
+.. code-block:: bash
+
+   Build/Scripts/runTests.sh -s buildCss
+   Build/Scripts/runTests.sh -s buildJavascript
+
+It is also possible to lint the files locally:
+
+.. code-block:: bash
+
+   Build/Scripts/runTests.sh -s lintScss
+   Build/Scripts/runTests.sh -s lintTypescript

Documentation/Index.rst

@@ -65,6 +65,7 @@ On these pages you will learn how to become a TYPO3 Core contributor.
 
    ReportingAnIssue/Index
    BugfixingAZ/Index
+   Build/Index
    AddingDocumentation/Index
    Testing/Index
    DebuggingTypo3/Index