plugins for bluetoothd

Hello,

I want to start writing a plugin for bluetoothd, but am getting stuck
on some problems. What defines when a plugin is loaded? Is it possible
to load a plugin without actually having to connect the piece of
hardware?
I thought it was possible to do it with /var/run/sdp but it seems not.

I have also been looking for a reference of what exactly can be done
over /var/run/sdp but haven’t found anything.

I know these are probably well known questions, but I would appreciate
being pointed in the right direction since I haven’t found anything.
Thanks,
Carlos