Developer reply by Ai Takeuchi
Rated 5 out of 5 stars
Hello,
This is one of the most usefull Adons in Firefox!
Is there any chance porting this to Firefox 115?
About version 115 support.
After some research and trial and error, we decided to take a different approach and create a different extension.
https://addons.thunderbird.net/en-US/thunderbird/addon/filtered-folder-to-favorite/
The results of executing the filter have been changed to display in "Favorites".
As a result, the unstable operation has been resolved.
For those who used this extension and "Favorites" together, it may have been difficult to use.
To create your own collections, you must have a Mozilla Add-ons account.