Why I cannot see and install the latest version of NeoVim 0.5?

Question

I added and updated Debian's experimental distribution to my source list which should contain neovim 0.5.0-1.

deb http://deb.debian.org/debian experimental main contrib non-free

When I run apt-cache policy neovim I can see only 0.4.4-1

  Installed: (none)
  Candidate: 0.4.4-1
  Version table:
     0.4.4-1 500
        500 http://deb.debian.org/debian bullseye/main amd64 Packages

If I run apt-cache policy nano I can see the latest version from the experimental.

apt-cache policy nano
nano:
  Installed: 5.4-2
  Candidate: 5.4-2
  Version table:
     5.8-1 1
          1 http://deb.debian.org/debian experimental/main amd64 Packages
 *** 5.4-2 500
        500 http://deb.debian.org/debian bullseye/main amd64 Packages
        100 /var/lib/dpkg/status

Answer 1

If you scroll down to the bottom of the neovim package page for experimental, you can see that it’s not available on amd64. That’s because it fails to build there (the build timed out).

A useful tool to figure this out locally is rmadison, in the devscripts package:

$ rmadison neovim
...
neovim     | 0.5.0-1        | experimental            | source, i386, ppc64el
neovim     | 0.5.0-1        | experimental-debug      | source

You could add the i386 architecture with dpkg --add-architecture i386, and install that version of the package; or wait for the build to be fixed.