This feature stores a list of files that have been recently opened.

freedesktop.org Desktop Bookmark Spec

A standard for storing a list of recently used files has been proposed by freedesktop.org. This list is stored using the XBEL format. The standard location for the data is $XDG_USER_DATA/recently-used.xbel which is often in $HOME/.local/share/recently-used.xbel. This standard is used by most GTK applications.

Tools

evince

When opening a new instance of Evince (with no arguments) or using the menu to select the "New Window" option, a canvas is shown that lays out thumbnails of recent documents along with their embedded PDF title metadata or filename if the metadata is not available. The number of documents shown on a single screen depends on the window size.