FILE MANAGER EXTRAS are additional options to customize Blogs, Books, and Mini-Websites.
Go to More Actions >> Options. What extras are available depends on the Layout - a Blog will have different extras than a Book, for example.
The important field is usually the Byline - it will publish your public profile, either as a Sidebar item, or as a Header. Your own User Name will be suggested: if you are the Owner, it is possible to write a different User Name (the user would still need to set his / her own profile to Public for any information to be shared).
Checking the Sidebar box will display some custom Sidebar features for this particular Layout. For example, a blog would display an archive, and a book would display its Tables of Content. Not all Layouts have custom Sidebar features.
