sys-apps/sandbox and other apps who installs xdg launchers in /usr/share/applications should be extended with a new local use flag : xdg-launcher-icon-* - where the * is replaced with the app name. so everybody can decide if they want a globally installed launcher icon for their package on their system or not. Reproducible: Always
This fits also for some games who installing launchers for servers and mapeditors where each one should be seperatly (de)selectable
we have no such policy or standard in the tree. if you don't like something, use INSTALL_MASK to locally remove it.