We have a multi-project set-up where there is shared UI & code. The setup we currently use is: - Main | - OurPackage-UI | - OurPackage-Core | - ProjectA | - ProjectB ProjectA & ProjectB manifest files reference the shared packages (e.g. "com.our.ui": "file:../../OurPackage-UI"). This has worked incredibly well. I really want to stress that this has been a somewhat revelatory workflow for us. Source control, third party assets, editing code/assets/ui in either project etc - it's beautiful. With one exception: UI Toolkit. *Update* 2021.2 now working similar to 2020.3 for us. We were having issues related to the uxml files not being recognised as VisualTreeAssets and not opening in UI Builder but his turned out to be that they were converted incorrectly. We then had issues with the stylesheets not loading. Once we removed all references to our package in the styles and made the paths relative again, they loaded fine. Now that we're back up and running, I would like to take this opportunity to ask that the team continue to keep our use-case in mind. Being able to work with UI TK assets outside of the project folder is very important to our workflow. Many thanks!