Asset library loading uses the file browser backend (file-list), so it would use the same job type. The job system makes sure that jobs of the same type (or actually, with the same start callback) wait for others of the same type to finish. This can be a problem here, since loading asset libraries (which can take a while) could conflict with regular file browers. Having both run in parallel is no issue, they use local data only. Also see #123033 to address the added TODO comment. Fixes #121235 Pull Request: https://projects.blender.org/blender/blender/pulls/123027