The LibrePCB application itself does not have any libraries bundled. Instead, libraries are installed and updated independent of the application. This gives you the full control over the library management — you can install either our official libraries, use your own libraries, or a mix of both.
If you like to use our official libraries, the integrated library manager allows you to install and update them in a few seconds. No manual file download is needed.
Since a LibrePCB library is just a directory containing some files, you can easily put every library under version control with the version control system (VCS) of your choice. A typical setup is to manage the official LibrePCB libraries with the integrated library manager, while using e.g. Git to manage private libraries.