Supermodel (Simple Version)
Why can't I see the addon under "Get Extensions"?
It currently does not have a "blender_manifest.toml" file yet, so you can install it the old fashion way under "Add-ons".
Why won't my "Circularize & Inset" work?
Enable Blender's "Loop Tools" for access to the "Circularize" action. Install it in later versions of Blender under "Get Extensions".