The workspace library holds every document in your workspace, whichever project it was added to and however it arrived. Use it to find a document when you are not sure which project it sits in, and to reuse the same document across several projects without uploading it twice.
Open it from Settings > Library.
Browse and search
The library has two views:
Folders: the folder structure mirrored from your connected drives, plus anything uploaded directly
By project: the same documents grouped by the project they belong to
Use the search box to find a document or folder by name, and the filters to narrow the list.
Add documents to a project
Select one or more documents in the library, then choose Add to project and pick the project.
You can also work the other way round. On the Documents page of a project, open Add Documents and choose Add from library to pick from documents that are already in the workspace.
Adding a document to a project does not copy it. The same document is now visible in that project, and it stays in the library.
Remove a document
There are two different actions, and the difference matters:
Remove from project takes the document out of that project only. It stays in the workspace library and in any other project it was added to.
Deleting the document from the library removes it from the workspace entirely.
Check status and retry
The library shows the same processing status as the Documents page. If a document failed, open its action menu and retry it. For a folder synced from a cloud drive, you can trigger a fresh sync from the folder's action menu.