Have you ever wanted to create a Paper fork that has multiple Paper forks as its upstream? Me neither. But thanks to this absolute trainwreck created by someone who just used Kotlin and advanced-ish gradle for the first time you can!
The system supports creating upstream-specific patches. They live in the patches/<upstream>-api and patches/<upstream>-server folders.
When applying patches, all upstream-specific patches for your upstream will be copied into the regular patch folders.
When rebuilding patches, they will be moved back to their own directories.
To create an upstream-specific patch, simply start the title with the name of the upstream, e.g. Purpur - Remove flying squid.
To switch upstreams, change the upstream in gradle.properties.