There are no longer separate Event and Project libraries, they are all in one place now, the Libraries pane.
Drives contain Libraries, Libraries contain Events, Events contain Projects and media, that simple.
They will be moved into a new folder titled “[drive name] Old Final Cut Projects and Events”.
Or you can move them to the TRASH (only for the brave).
They do present a paradigm you should wrap your head around and plan for before upgrading.
They are easy to understand and give us much more immense power and flexibility in managing large amounts of media in our daily work. Will you make one Library for each production, and Event for each scene?
FCP will create a folder titled “Final Cut Pro Backups”.
FCP X 10.1 will then go through an analysis and updating process. This final update window will allow to you SAVE your current Event and Project folders (highly recommended).
They will be moved into the OS X Trash, but the Trash will not be emptied.
A final word on upgrading to 10.1 libraries: based on my personal upgrading of three FCP X systems to 10.1, empty Projects may be completely deleted, though technically they shouldn’t.
This is done via the Open and Close commands in the File menu.
Before updating from a previous version of FCP X, please read this section completely.