As the name would suggest, this default type of menu does not change in any way, and may be manually edited and/or (re)generated automatically through the use on an appropriate software package.
Fast and efficient, while this type of menu can be used to select applications, it can also be useful to access specific functions and/or perform specific tasks (e.g. desktop configuration), leaving the access of applications to another process (e.g. the synapse or xfce4-appfinder applications).
The ~/.config/openbox/menu.xml file will be the sole source of static desktop menu content.