rmc is a mailcap [0] implementation, written in perl.

rmc is intended to be more general-purpose, than the original RFC
suggests, and be useful in situations where xdg-open [1] may be
useful. The implementation is not 100%-compliant: some parts of the RFC
are intentionally violated.

You can download one of the releases at [2], clone the git repository
via [3], or browse it at [4].

[0] https://www.rfc-editor.org/info/rfc1524
[1] https://www.freedesktop.org/wiki/Software/xdg-utils/
[2] {ftp,rsync,https}://manpager.org/pub/usr/aa/rmc
[3] ssh://anon@git.manpager.org/rmc
[4] https://git.manpager.org/?action=summary&path=rmc.git