vcswatch reports that
this package seems to have new commits in its VCS but has
not yet updated debian/changelog. You should consider updating
the Debian changelog and uploading this new version into the archive.
Here are the relevant commit logs:
commit c2ddff46b3f7e6d4e7cace7f876a14cc5a5d38ac
Author: Pavel Sanda <sanda@lyx.org>
Date: Fri Jan 1 17:38:51 2021 +0100
Mythes was actualy moved, not removed.