HP 3000 Manuals

HPTOOLSET XL Reference Manual

Mainkeys Function Key 

The Mainkeys function key is located in the Debug function key loop and
in the Copylib Editing function key set.  It is a branching key which
returns you to the main function key loop.  When you are in the main
loop, DebugKey can be used to return to the Debug loop and Lib Keys will
return you to the copylib editing keys.

MPE/iX 5.0 Documentation