What is libertas_devs[] and libertas_found for?

[Holger Schurig]

What's the reason of the code around libertas_devs[] and libertas_found 
in main.c?

Is it common for any USB driver to have an upper limit of possible 
devices, to have a local list of those devices and to fiddle with this 
lise in XXX_remove_card as well as in the module exit code?

Doesn't usb_deregister() handle this for us and call the .remove 
function anyway?