Blackhawk holster mounts

Hey, I have a Blackhawk holster, it has two holes on the top/ rail side of the firearm. It looks like it has space to put screws through and attach an item, except I can’t find anything that says it mounts to it. Does anyone have an idea of what does mount to these two holes? I see some tourniquet mounts but nothing seems to mount directly to the holster, thanks for any info