Transient is the library used to implement the keyboard-driven menus
in Magit.  It is distributed as a separate package, so that it can be
used to implement similar menus in other packages.

You can contact the maintainer of this package by sending an email to
<emacs.transient@jonas.bernoulli.dev>, or you can use the public issue
tracker at <https://github.com/magit/transient>.  The latter can also
be accessed using the `forge' package, which lets you avoid the sadly
non-free javascript on that website.