I’m not an expert in this at all, Try this website: http://mgex.igs.org/IGS_MGEX_Data.html . It seems to address the crx.gz files as containing the observation file in compressed form.
It appears that this is new stuff. Most USA sites are only GPS or GPS + GLO. It appears that your base station covers GPS, GLO, GAL, CIN, etc. The files appear to be in the new compressed format.
I believe the RTKLIB pdf manual covers use of the compressed format, but not sure.
I think Base obs file is not requested if not needed as in Single mode.
It’s hard to see what the units are in the .jpg image, but for a baseline of 68.5 km, the FIX would appear to be impressive. Perhaps you could elaborate on your Base Station, etc. Maybe you can help some of us…