MODs allowed this with the Author Notes section in the MOD.XML file.
This is always a good place to tell the user where they may find any settings/controls to their new extension. Where they may be able to find extra support (links). Or any information they should know about the extension they just installed installed, like if it needs permissions created before it will appear to work, how it all works (if its complicated), etc.
I think this could be added to the "Details" link of the extension manager, and added to the Composer.json metadata under the label of "Author Notes" and could come after the requirements, but before all the Author Names are listed on the details page.
Authour Notes: You can configure this extension's settings by visiting the "Extensions" tab above. The extension was installed in a disabled state, so you will need to enable it to take effect. You can adjust how many foobars it displays and use phpBB's caching feature to speed up its performance. Most importantly, you should also visit the Permissions tab above -> Group Permissions and define which groups you would like to be able to use the features of this extensions. Further support can be found at http://www.phpbb.com/myextnesionslocation"