The "F" in MouseText is the character used to represent a carriage return,
sort of like this:
|
|
<----|
The "G" displays four horizontal bars, an Apple II representation of an active
(or foremost) window. It looks like this:
________
________
________
(this space is intentional)
________
You'll find a list of MouseText characters in the Apple IIe Owner's Manual
(platinum), page 133.