Duplicate Tabs Cleaner од Denis Oparin

Duplicate Tabs Cleaner removes duplicate tabs after Firefox startup.
The extension:
* checks all open tabs 3 seconds after startup;
* considers tabs duplicates when they have the same URL and the same Firefox container;
* keeps tabs with the same URL if they belong to different containers;
* closes duplicate tabs and keeps the first occurrence.
No account or website login is required for testing.