See "pod2man --utf8 contrib/i3-dmenu-desktop | man /dev/stdin" for
documentation. Use a line like this in your i3 config file:
bindsym Mod1+p exec --no-startup-id ~/i3/contrib/i3-dmenu-desktop
contrib is a place for scripts which live in the i3 git repository
because they are closely related. However, they should not be shipped
with the distribution packages for example.