The [[Special:Watchlist]] page shows a legend block. Alignment of items inside this block looks a little weird.
This is caused by dt element sharing a style block with headers, which have: margin: 1.5em 0 0.5em. This makes their height larger than the line-height of single line dd elements following them.
If that margin was intentional, then it was probably supposed to be on the <dl> element instead. And maybe it's just a complete oversight :)
Anyway, dt's are not headers and should not be treated like such.
Should now be properly resolved in https://gerrit.wikimedia.org/r/c/mediawiki/skins/Timeless/+/501850, which should go out next week.
(Forgot to tag this because I didn't realise this hadn't already been resolved, and thought I'd reintroduced it and then had to fix it again.)