Run `yarn dev` and `yarn prod` (with env vars pointing at a custom repo) and check if it correctly serves files. Example:
`HAZEL_ACCOUNT=MichalGniadek HAZEL_REPOSITORY=comm-test-gh HAZEL_PORT=3005 yarn dev` will use this repo: https://github.com/MichalGniadek/comm-test-gh that already has some releases with necessary files created.