Try it on Demo Company's cache page: fetch each card twice and watch a download, a 304, and a copy used with no request at all.
The rules: HTTP caching (RFC 9111) and conditional requests (RFC 9110).
The narration is a synthetic voice (ElevenLabs). Timing follows the narration track, so a recorded voice-over can replace it cue for cue using the transcript.
With Reduce Motion turned on in the operating system, the film keeps its fades and drops the sliding motion.
Set in Atkinson Hyperlegible Next and Mono, typefaces the Braille Institute designed for readers with low vision.