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 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.