It is perfect, fix the FF issue when you accidentally close the pinned tab windows first. Thank you, you saved tens of hours to restore pinned tabs. The pinned tab sets it is also very useful!

One of the few addons that works with Pinned tab groups.
Allows Load/Hide/Switch of Pinned Tab Groups.

Works great with Simple Tab Groups (STB) to manage load/save/switch tab groups (STB doesn't load/hide pinned tabs).

Doesn't save which container the tabs are in. Always loads tabs in default container.

Works as expected. I do not understand why this isn't standard in any browser. Thank you!

A recommendation:

https://github.com/Drive4ik/simple-tab-groups/issues/286#issuecomment-787110861