The debug build (ENABLE_SERIAL=ON) compiles out tud_connect/disconnect and enumerates as a serial console, not a working HID/audio bridge — an end user who downloads it gets a non-functional dongle. Keep it buildable on demand (-DENABLE_SERIAL=ON) and in build.yml PR CI for compile coverage, but don't ship it on the public release page. Releases now upload the standard UF2 only. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>