Image::MetaData::JPEG::Structures(3pm) on Linux
The text 8550a99130f9, as Debian 10 (Buster), Debian 9 (Stretch), Debian 8 (Jessie), Debian 7 (Wheezy) shipped it.
This document describes the structure of a JPEG file; it is an appendix to the main manual page of the Image::MetaData::JPEG module, which the reader should refer to for further details and the general scope.