Read Dan’s blog post about the process of making Stack Overflow more accessible.
We followed the Web Content Accessibility Guidelines (WCAG), with a few exceptions. For example, we chose to measure color contrast using the Accessible Perceptual Contrast Algorithm (APCA).
We quantified the accessibility of our products using the Axe accessibility testing engine.
Our accessibility dashboard helps our internal teams and the community track the accessibility of our products: Stacks (our design system), the public platform (Stack Overflow and all Stack Exchange sites), and Stack Overflow for Teams (including Stack Overflow for Teams Enterprise products).
We also implemented robust accessibility testing and made those rules open-source in a comprehensive package you can find here.
Shoutout to user Beejor for an excellent answer to the question What is the largest safe UDP packet size on the internet?.