nostr:npub1kpwlxpzkxfmuxjmzc2wp3rf9vjg0sgydmlhsnrgqr3maf59h86qqdxxzz4 

No, that was not what was meant.

More info via this link.
It is native to Firefox Android and does not require installing additional add-ons.

https://blog.mozilla.org/en/products/firefox/get-organized-with-firefox-collections/

The Firefox for Android app lets you collect and organize tabs into any quick grouping you want. You can create and name your own Collections and add pages to them as you browse. To add any tab to a Collection, tap the three dots, then tap Save to collection.