Previously I've been able to mouse-click a card to review its side, but now it requires keyboard use which is less comfortable for my use-cases... I didn't see anything about that in the changelogs, so it might be a regression.

Thank you, that works. (extra stuff because message must have minimum length)

This was a deliberate change, but it also comes with a setting to restore the original behavior in Settings → Review settings → Display a button to reveal the next side.