While every CurseForge upload of JER includes two additionals files (api and sources), modrinth doesn't. However, these files are extremely useful when adding JER as a dependency. Also, from my experience, the modrinth maven works much better that the CurseForge one, and also has more readable dependency coordinates.

In order to use the modrinth maven for JER dependencies it would be very helpful, if the api and sources jars were uploaded to modrinth as well.

Have this on the to do list, will give some higher prio to it