Merge stable into master

docs/builds/guides/development/custom-builds.md

@@ -35,7 +35,7 @@ In order to start developing CKEditor 5 you will require:
 
 ## Forking an existing build
 
-Start with [forking](https://help.github.com/articles/fork-a-repo/) one of the official builds (it will serve as the starting point for your custom one) and then clone your fork:
+Start with [forking](https://help.github.com/articles/fork-a-repo/) [the main `ckeditor5` repository](https://github.com/ckeditor/ckeditor5) (it will serve as the starting point for your customizations) and then clone your fork:
 
 ```bash
 git clone -b stable git@github.com:<your-username>/ckeditor5.git