[Observium] MIB files to compile?

Hi there,

this may sound a bit stupid but I need to know this for sure: MIB files in Observium don't have to be compiled but to be available under /opt/obersium/mibs/ or(!)/opt/obersium/mibs/[vendor]? Background is a strange feeling that some MIBs are not used at all - so the second question is: how to validate that Observium uses the correct ones so I can verify either that I've done something incomplete or the affected MIBs are not valid or incomplete at all.

Thanks in advance! Björn