[scroll-animations-1] Early Horizontal Review

[fantasai]

• A11y review requested
• I18n review requested and completed
• Privacy review [seems inapplicable; skipping until later in the process]
• Security review [seems inapplicable; skipping until later in the process]
• TAG review requested and completed for ED; requested and completed for 28 April 2023 WD

[flackr]

@fantasai Are we ready to start the next round of the TAG review? I think the overall shape isn't likely to change much between now and closing out the remaining issues.

I've started a draft of an updated review request.

[flackr]

Another TAG review round is started:
w3ctag/design-reviews#828