March 6, 2023 Hotfix!
Basically, many volumes had incorrect series ids, which would lead feed entries to generate bad links. While the fix only took a few minutes, I had to release with the Kodansha US update, which adds nearly 600 new volumes! So those series are being released several days earlier than planned, before I could run through my normal release process. Expect the full changelog on the 11th.
But feed urls should work again!