Some of requirements are,
- Striker fired pistol with constant trigger weight from the first to last shot fired. Trigger pull must be between 4.5 to 6 lbs
- no decockers
- must be able to use magazine from full size in compact version
- should carry 16 or more rounds for full-size, 14 or more for compact. mechanism should be same
- grip must have replacable panels to adjust for different hand sizes
- no finger grooves
- magazine should have holes to check how many rounds are in there, at least one hole for 5 rounds. Followers preferably has high visibility colors.
- controls(slide lock, magazine release) must be ambidextrous and bea easily accesible from either sides. Magazine release has to be activated by lateral pressure.
- no external, grip safety
- front and rear night sights, high visibility sight such as Trijicon HD preferred
The contract is minimum $25 million to $85 million over 10 years. It also includes Simunition pistol, training pistol, and parts.
The discussion seems to speculate that this is a way FBI is nudging Glock to update their offering. A lot of specifications can be met by various manufacturers if they change a few things. Currenty, out of commercially available guns, SIG Sauer P320 seems to be a contender.