Section 5 of the manual describes various file formats, as well as the corresponding C structures, if any.
In addition, this section contains a number of pages that document various filesystems.
Authors and copyright conditions
Look at the header of the manual page source for the author(s) and copyright conditions. Note that these can be different from page to page!
This page is part of release 5.07 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.