🚀 go-pugleaf

>...if someone could just send me specifications for the PG (the
> documentation that comes with says: plug in the board, turn on
> your PC) and for MS Windows drivers, I could write my own!...

There is detailed documentation for the PGA in

The IBM Options and Adaptors Technical Reference Manual UPDATE
dated 15 August 1984.

I got mine by sending in the yellow card that came with the Options and
Adaptors manual (6322509).  Said manual is 2 volumes long, costs at least
$125.00, and does not contain anything about the PGA.  The UPDATE to the
manual includes a third volume and info about the PGA, the EGA, and many
other things.

There's more...

I got a letter from IBM almost immediately afterwards, saying that said
update service had been DISCONTINUED, and implying that one should order
new manuals if one wanted updated information.  I called the number on
the letter (800-IBM-PCTB).  The person who answered the phone knew nothing
of any of this, but called someone else to find out.
The bad news: You now have to pay for updates.
The good news: You now can buy the updates without buying the manual.

For the PGA, The update you want is 6280133, which costs about $27.00.