Currently, if handles are changed, tangled repo links break which obviously hurts the ability to share links (especially as people are more likely to change handles through something like atproto when your domain is your handle on a social media platform than they may be on a typical git forge). I felt it was worth noting and suggesting some ideas of options to help people reduce this problem.
1 - "Legacy" handle support
I think one option that would be useful is for users to add DNS for their old handles that Tangled can access to certify they do indeed still own their domain. I'm unsure how precisely this could be resolved for names that are based on a subdomains people don't personally own (other than .tngl.sh where support could be more easily implemented).
I think maybe the best practice would just be to warn users that changing their handle has altered their links and so old links may not work when they next open Tangled, directing them to where they could add legacy handles. I'm unsure how much this would clash with the protocol itself, but I think this could be useful as I imagine tangled users are on average more likely to have custom domains than most protocol apps.
2 - Adjust "Page Not Found" to offer to search for repositories with the same name
This is obviously a quicker, easier solution that I don't think is mutually exclusive to the previous option, where there could be a custom page for if the structure of the domain aligns with the url structure of a repo, it could tell the user the page wasn't found but offer the option to search for similar repos, with a search bar (or button) populated by useful metadata (whether that's just what the part of the url that would be the name of the repo itself, or whether that's including what would be the handle, too). This obviously doesn't fix the issue directly, but it reduces the friction of the experience for the end-user who's just trying to explore the repo/issues/etc and may think it's just been deleted. Now there is search functionality, it seems an easy way to help resolve this.
I'm sure other options than these may be better than either one, but I felt it better to offer some proposals that could help rather than just complaining lol