Section 508 is the general description we use to refer to Section 508 of the Rehabilitation Act of 1973, as amended 29 U.S.C. § 794(d).  …and yes, the actual document is just as dry as it sounds.  If you really want to read it, you can search for 29 U.S.C. § 794(d) online or see Access-Board.gov.

In plain English, though, Section 508 basically says that

1. Equal access to office systems (electronic and information technology) should be provided to Federal employees with disabilities
2. Equal access to government information should be provided to those in the general public with disabilities.

There is, of course, an “undue burden” aspect, but that’s for the legal experts to examine.  For our purposes, Section 508 tells us that government materials (on websites, documentation, and other media) should be readily accessible to people with visual, auditory, or motor disabilities.