No horizontal scroll in Safari. Bug, or pref?
It's an issue with AdGuard, specifically the Web Annoyances Ultralist.
Reported to the developers in https://github.com/AdguardTeam/AdguardFilters/issues/82833
with a dev response

Ok, better disable this filter. It can break something in Safari, also our filters compiler has one issue AdguardTeam/SafariConverterLib#21
After release which will contain the fix for problem above, you can try that filter again.

I have that filter disabled for now &amp; will test again after the next release.