All of the official LibrePCB libraries are hosted in repositories on github.com under the username LibrePCB-Libraries and are available for download. They are also mirrored on the LibrePCB.org library server. Anyone wanting to donate to these libraries must have a github.com account and follow the procedures outlined in this document.
Librarians should always create a separate LibrePCB workspace and only use it for editing libraries. Edits can only be done on local libraries and you cannot have a remote copy of any library that you are working on in the workspace.