Here's a list of RPO codes. It's 412 pages long.
https://rparts-sites.s3.amazonaws.co...n/rpoCodes.pdf
Here's a couple of your RPOs
GU6 - 3.42 gears
G80 - positraction rear axle
L35 - ENGINE,4.3L(4.3W),CPI,V6,90 DEG
M30 - TRANSMISSION,AUTOMATIC 4 SPEED,4L60E,ELECTRONIC
ZQ8 - SPORT CHASSIS PACKAGE