a11y is short for "accessibility".

a11y identifies what the viewer is watching, then augments it by delivering sign language (for the Deaf), and/or captions (Hard of Hearing). Audio description support (for the blind/visually impaired) will be included in a future version.

To briefly test/demo the app, use a computer or laptop browser and go to:
https://www.a11y.media/demos/v/beginnings; or
https://www.youtube.com/watch?v=U4VnZz_-z1U;
then press "Start" in the app.