At the moment two "busy" packages exist:
They do exactly the same thing. They have a almost the same API and functionalities. But there are two of them.
This package (ironically installing another one seems to be the only solution) acts as a bridge between
busy-signal, pretending to be
busy-signal must not be installed for this package to work
Good catch. Let us know what about this package looks wrong to you, and we'll investigate right away.