Rationale: I'm quite annoyed with people whining "pAyWallED!" in news post comments, and this is Tesseract's way of addressing that (for users of that UI, anyway)
Description:
On posts with links (that aren't images, audio, video, Youtube, or other media), a dropdown menu is added with links to alternate sources.
Each one will search for the URL in the selected archive provider (currently Ghost Archive, Archive Today, 12ft.io) or Ground News (new in 1.4.5).
Lemmy-UI kind of does this, but completely ass-backwards (only during post creation to set the post link; I'll spare you my spiel about how that's a horrible vector for misinformation).
On Youtube-like posts (YT, Invidious, or Piped), the options are changed to go to the canonical YT link, your preferred Invidious instance, or your preferred Piped instance, but that's just a secondary (but still nice) feature of that component.
Would love to see something like this more widely adopted and am more than happy to answer any implementation questions.