Just migrated a website with a theme based on Unyson Framework to Bedrock and wanted to share the approach in case anyone finds it useful or has input.
Unyson itself is available via composer at wpackagist-plugin/unyson however the “extension manager” didn’t seem to be working.
The extensions are, by default, stored within the plugin directory at: web/app/plugins/unyson/framework/extensions.
So what I first tried was to add !web/app/plugins/unyson/framework/extensions to .gitignore, then add that directory to the trellis/site repository: git add -f web/app/plugins/unyson/framework/extensions.
That approach ended up not installing unyson. So now I have just manually added the entire plugin and select extensions to the repository, and removed unyson from composer.json.
Not sure if there is a better way at this point. Looks like there has been issue posted.