As far as I (vaguely) understand there should not be several “modellib.bgl” files on a system as only the last one of them being loaded, see e.g. here.
Bad_T’s Addon Linker provides a function to find (and rename) doubled Modellibs. I ran this and as a result got an extended list of I would say several hundred items. The Linker provides me a possibility to rename all these, but I am hesitant to do so.
The list contains all sorts of sceneries, freebies from Flightsim.to but also Payware from Gaya, Aerosoft, FSDG, and the like. Did all those developers not comply to the MSFS SDK? And if I rename them, what happens in case of an upgrade, notably via automated upgraders like Aerosoft One or ORBX Central?
Thanks for an explanation and suggestion what to do.