The MATTERDENS in the VAC (slimeMold_galaxy_catalog_v1_0_0.fits) is the local 
density at the location of galaxies in the catalog. However, we also refer those 
interested to the full 3D density field of the relevant volumes at
https://data.sdss.org/sas/dr17/eboss/lss/mcpm/v1_0_0/datacube .
These can be queried using the code pyslime available at
https://github.com/jnburchett/pyslime 
by first decompressing each trace.bin.bz2 density cube.