1662630 - Add a "de-duplicate tabs" option to the tab bar's "Close Multiple Tabs" sub-context menu

Status: RESOLVED DUPLICATE of bug 1891797

(Firefox :: Tabbed Browser, enhancement)

Description

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

Over time, I sometimes end up with identical urls opened up into multiple tabs. It would help me a lot if there was a "De-duplicate tabs" option included in the tab bar's context menu under the "Close multiple tabs" submenu.

Unsure/indifferent about which tabs get counted as the to-be-closed duplicates. I guess the right-most duplicates in the tab bar get closed? If tab "age" is tracked, maybe close the newest instances? Maybe ignore pinned tabs completely, even if they would be considered duplicates?

Steps:
Open three tabs to https://google.com
Open two tabs to https://bing.com
Open one tab to https://amazon.com
If the yet-to-exist "de-duplicate tabs" option is clicked, the end state is one tab to each of those three urls.