The 17.0 major release is coming on May 16, 2024! This version brings many exciting improvements to GitLab, but also removes some deprecated features. We are introducing three breaking change windows during which we expect breaking changes to be deployed to GitLab.com. You can read more about it on our blogpost. The third breaking change window begins 2024-05-06 09:00 UTC and ends 2024-05-08 22:00 UTC.
In response to !23 (merged), absorb theme macro into modus-themes.el and delete modus-themes-core.el. I've forward declared some variables so the macro is where you expect it to be. As always when fiddling with macros, this works on my machine but I would feel a lot more confident if you also tried it on yours.