In plain language
Any time limit must be removable, adjustable (10x), or extendable with at least 20 seconds' warning.
Who it affects
People who read, type, or move slowly, including many screen-reader users.
How to check
Find every timeout (session, form, redirect): wait it out and verify a warning with an easy extend option, or a setting to turn it off. Worked example — A food-delivery app's order-tracking screen: check any 'adjust the timeout' setting: it must let the user set the limit to at least 10x the default — a smaller multiplier fails.
Common misconception
Session timeouts are often treated as a security requirement that overrides accessibility. In reality, WCAG just asks for a warning and a way to extend it, which doesn't weaken security at all. Real example: on a podcast app's episode list, the page uses a timed auto-redirect (meta refresh) — users are moved to another page before they may have finished reading.