When you have A LOT of files in your team, and many are published team libraries, the only way to know which files are libraries is to go into some file, go to the assets panel, click on the library icon, and scroll through all available libraries. If you want to unpublish a library, you then have to go back to the browser, find that file, open it and unpublish it.
A better way could be to simply take the chance of these new icons which differentiate between Figma and Figjam files, and add a type of file icon for published files:
