From the website yes you can. It shows past and future releases of debian packages. I personally don’t actually know how to search repos without adding them to your apt lists, as I believed that can potentially create a frankendebian.

scrcpy is in bullseye-backports and sid, but not bookworm

https://packages.debian.org/search?keywords=scrcpy

I don’t have Debian installed right now so I don’t want to give bad advice. When I did use Debian I think I just compiled it myself.

I can do something like this:

[\ #84]  apt-cache policy scrcpy
scrcpy:
  Installed: (none)
  Candidate: 1.25-1
  Version table:
     1.25-1 500
        500 http://deb.debian.org/debian unstable/main amd64 Packages

And it tells me that, for me, scrcpy is available from the main repository in unstable. Not sure how to find a package if it isn’t in one of your sources. I guess you could search for the package at https://packages.debian.org/index.

https://www.debian.org/distrib/packages could be a place you may find it. But apt-file did not find it from my sources list, so I hope you will be luckier.

No. If you want only one package from contrib, you can add the repo, pin it below your others, then pin scrcpy from contrib above the others. That should do what you want.

https://wiki.debian.org/AptConfiguration

Thank you all. That’s what I thought - no way to make the query the way I was thinking of.

I realize that, if i’d like to have a program search for repos not configured in sources.list, then I would have to specify the repo as well (the https:// link, I mean).

The website half-fixes the problem, since it tells me the release the package might be in. But still doesn’t tell me whether it is in main, contrib or non-free (section?).

Don’t worry about me creating a frankendebian by mixing releases - I destroy my system in other more subtle ways like adding appimage applications as if there was no tomorrow.