/usr/share/xsessions/openbox.desktop is in openbox 3.5.0-2ubuntu2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 | [Desktop Entry]
Encoding=UTF-8
Name=Openbox
Comment=Log in using the Openbox window manager (without a session manager)
Comment[pt_BR]=Use esta sessãpara executar o Openbox como o seu ambiente de trabalho
Exec=/usr/bin/openbox-session
TryExec=/usr/bin/openbox-session
Icon=openbox.png
Type=XSession
|