There's no TeX Hour tonight because the 2021 TeX Conference has already started. There'll be an accessibility TeX Hour next week. The topic will be technical obstacles to Accessible TeX. It will be informed by 8 talks at the TeX Conference.
TeX Conference and accessibility talks
You'll find live streams from the TeX Conference at https://www.youtube.com/c/TeXUsersGroup
. From 11:00am to 14:00pm tomorrow (UK time) there'll be 4 talks on math accessibility, and another 4 talks from 20:30pm tomorrow to 0:45am the next day (UK time).
with best regards