There's a few issues that are labelled with 'backend: Docker' that are actually about Environments. Should we have a separate label for those? E.g. https://github.com/pantsbuild/pants/issues/18889, https://github.com/pantsbuild/pants/issues/18915

Sounds good to me. I created

backend: Environments

. It's arguably not exactly a backend, but feels close enough; it looks like it can be renamed if someone hates it a lot (and if people hate the concept too much, it can be deleted)