This is a collection of so called „Service Menu“ scripts for Dolphin from KDE SC.
General information about .desktop files can be found here.
Your .desktop files must be placed system wide (on Arch Linux) in
/usr/share/kservices5/ServiceMenus/
or for a specific user in
~/.local/share/kservices5/ServiceMenus/
Then restart your Plasma session or run:
kbuildsycoca5
Your .desktop files must be placed system wide (in Gentoo) in
/usr/share/kde/services/ServiceMenus/
or for a specific user in
~/.kde/share/kde4/services/ServiceMenus/
Then start a new instance of Dolphin.