I applied the workaround from emudhra.we-have-a-problem.com that removed the compromised certificates. Then ran the curl check:

curl https://dv-g3b-emudhra.we-have-a-problem.com/

and curl wouldn't connect.

I then installed the latest update for macOS Sequoia (15.8.2 (24H230)). When I now re-run the test I'm getting:

curl https://dv-g3b-emudhra.we-have-a-problem.com/

Your client successfully connected to the site. That's bad!

As far as I understand the macOS update has reinstalled the compromised certificates, and I have to re-apply the manual workaround again. I didn't expect that.