Four sealed bearings on the bottom of the sliding table guide it along the rails. The tile setter has removed the table to clean off the sludge and is spraying silicone lubricant onto the bearings.
When the pump is running, water is sprayed onto the blade through a pair of orifices at the rear of the housing.
The flap of shower-pan liner material on the front of the saw is not original equipment; the tile setter screwed it onto the blade housing to reduce “overspray” and keep himself dry. It’s not pretty, but it does the job.