Going through the issue queue for triage it would be helpful if the extension api was actually defined.
N/A
Define the api as the following:
Issues in the extension system component issue queue
Classes in the following namespaces
Drupal/Core/Extension
Drupal/Core/Hook
Module install and uninstall forms
Confirmation forms for modules install/ uninstall
(currently in system module)
Confirm list
Define any other responsibilities of the extension api
I'm least sure about the module install and uninstall forms but they feel relevant
Determine where to document this
Active
11.0 🔥
extension system