a note about versioning

README.md

@@ -30,6 +30,32 @@ Build a development version and watch:
 npm run watch
 ```
 
+## Versioning
+
+This repository has tags consisting of three numbers, for example,
+`0.1.0`, `0.1.1`, `0.1.2`, and so on. However, browser add-ons are versioned with
+two digits like `0.1`. The convention used here is that the "minor" (middle number)
+digit is incremented when there's a new add-on version, and otherwise it's 
+some other update: native messaging host, documentation, etc...
+
+Example:
+
+- git tag: `0.1.0`
+  - browser extension: `0.1`
+  - native messaging host: `0.1.0`
+- git tag: `0.1.1`
+  - browser extension: `-`
+  - native messaging host: `0.1.1`
+- git tag: `0.1.2`
+  - browser extension: `-`
+  - native messaging host: `0.1.2`
+- git tag: `0.2.0`
+  - browser extension: `0.2`
+  - native messaging host: `0.2.0`
+
+If you have a browser extension with version `0.1`, its exact source code
+can be found under `0.1.0` git tag.
+
 ## Protocol
 
 KeeWeb implements [keepassxc-protocol](https://github.com/keepassxreboot/keepassxc-browser/blob/develop/keepassxc-protocol.md)