I've got several assets files, which for some reason have unused linked-materials (from external other files). This results in a big list of useless "Libraries", visible in the Outliner, "Blender file" type of information.
I tried to delete the materials by hand, with Shift + Click on the "Unlink datablock" button, save the file, then reopen it, but materials are still there.
However, I tried to change the path of the linked libs by a non-existing file, directly in the Outliner, then saved the file and reopen it (twice). It worked. But too long and fastidious way to do that...
My question is : is there a quick way (with scripting or via UI) to auto-unlink unused things ?