Thanks to Jochen Merz I can now provide the QMenu (menu_rext) extension for download for free, including the original manual:

QMenu v8.04

QMenu v8 manual

; 8.04	Fixed QDOS compatibility broken in 8.03
;	FSEL Allow up to 8 devices
;	DSEL Now really allow up to 10 devices (buggy since 7.55)
;	FSEL/DSEL Ensure device selection keystroke is unique
;	LIST Fixed crash on editing of strings that are too big
;	LIST Redraw selection keystroke after string edit operation
; 8.03	First release by Marcel Kilgus
;	Fix QDT problem: LIST menu became too big with the move button. In
;	  this case we revert to the smaller menu of v7.65
; 8.02	Fix to run on all SMSQ/E systems, not just QPC
; 8.01	VIEW Upper-case word of nr of chars specifies nr of lines
;	SYSS Two spurious characters in Job name list of daughter jobs fixed.
; 8.00	VIEW Application colour used to display the view listing
;	SYSS SYS_SELECT$ properly implemented: History, Jobs & Things
;	FSEL A DO on the Previous button calls up buffer history

; 7.69	VIEW Start string considered on Refresh
; 7.68	LIST Fixed the fact, that menu items were 2 chars too large
; 7.68	LIST Window move finally implemented 🙂
; 7.67	LIST Autosize correct if selection keys given
;	LIST Long titles fit even in small menus
;	RPER Timeout for RPTR loop in upper word of colourway parameter
;	ITSL Timeout added as for RPER; return value if timed out is -3
;	RSTR Bit 6 set: negative sign allowed for numbers.
;	ITSL Window move implemented.
; 7.66	LIST Fix in Edit mode
; 7.65	High Colour version.