this is a greeter designed for mobile hardware. although most mobile DEs
are capable of running without an external greeter by using their own
lock screens, those tend to have different limitations. for example, the
lock screen in Phosh doesn't do PAM session management -- but by using
this lightdm-mobile-greeter which integrates with PAM, one can do things
like decrypt a home directory or unlock keys on login.
the upstream project lacks many images/videos, so here's what the
software looks like: <https://www.youtube.com/watch?v=whcFag0drLk>
