Its probably an epoxy sealant, sealing the surface so oil can not seep into concrete which is porous. I f you use this epoxy be sure to etch the floor with muriatic acid, wash and let it dry well or it will bubble and peel
muriatic acid is used to etch concrete, thats probably a little harsh , maybe a degreaser, I used to take wet the concrete down pour dish soup on it and scrub it with a stiff brush, it worked well for fresh spills, don't know how well it would work on stains that have been there a while.