In your irregular verb list 'alight' is defined as 'get off ...'.
As a birdwatcher I see a great deal of alighting on. In fact I would never have thought of a bird alighting off a branch; or the ground.
In my mind I always 'get off' a bus or train although signs in public vehicles do mention alighting.
I don't know about alighting on/onto a bus or train personally, but I have seen birds do so.
It seems that 'alight' is a subject-sensitive verb; there must be many others.
There may even be alight at the end of the tunnel.
I prefer 'alit' for the past form but usually 'alighted' sounds better (to me) as the partciple.
But the word is old-fashioned.
Both uses have the sense of "to come down". You alight from a bus, but a bird or butterfly alights on a branch.
There is also something alight which may a light at the end of the tunnel.