This is PM handling of
;INT 33 - MS MOUSE v6.0+ - SET LANGUAGE FOR MESSAGES
; AX = 0022h
; BX = language
V version accepts 8 [standard] languages, F - 10 (some additional 2 lanuages and IDK what they are).
It's strange but the variable where this value saved is referenced from other places in code - but there is only 8 languages processed.
No. It is workaround against buggy hardware - some PS/2 5-Button Mice.
In addition to standard unlocking sequence of Set Rate 200, 200, 80 it executes (when Registry "Enable Q318307" key is set to 1) nonstandard sequence of Set Rate 200, 200, 60 before standard sequence.
But problem still exists - VMOUSE.VXD from Q318307 has version 4.10.2225 (for windows 98SE for exаmple) and previous version from Q254660 is 4.10.2223.
So there is no such thing as VMOUSE.VXD 4.10.2224 and that is the real misterious.