Eclipse is a paper plugin that adds the fabric Mixin software to paper, allowing plugins to use mixin and accesswideners, without having to make their own patching software or needing to use workarounds, reflection, bytecode manipulation, ETC. It adds mixins the same way Fabric does, and stays up-to-date with the latest versions and features of fabric mixin. It also bundles MixinExtras, which is an addon to mixin that adds more capabilities to expand its functionality.

You can use the official spongepowered mixin libraries when using Eclipse, since it bundles those libraries automatically and uses them for running fabrics mixins. This plugin is still in early beta, so there may be issues. If you find any report it to the github repository.