User space startup programs can only start after the display manager has logged the use in.
Therefore, they must either be launched by the DM at the end of its operation, or by something spawned by it.
Used by Ubuntu, LXDE, KDE, GNOME
Specification by freedesktop.org: http://standards.freedesktop.org/autostart-spec/autostart-spec-latest.html
Configuration files under:
/etc/xdg/autostart~/.config/autostart/
Each file gets sourced.
Example, in a file called firefox, put:
[Desktop Entry]
Type=Application
Exec=firefox
TODO who executable implements it? Which DEs adopt it?
Ubuntu 15.10 has gnome-session-properties from package gnome-session-bins is a GUI editor for those file.
Enable or disable one of the startup files:
X-GNOME-Autostart-enabled=false
X-GNOME-Autostart-enabled=true
You could of course remove it, but this is better as it keeps the rest of the data.
Renaming the file to something like file.desktop.off is another option.