The Combat Feat "Dirty Fighting" (https://www.d20pfsrd.com/feats/combat-feats/dirty-fighting-combat/)
Source: Paizo Inc. - Pathfinder Player Companion: Dirty Tactics Toolbox, p.14
In the "Special" Description states:
"Special: This feat counts as having Dex 13, Int 13, Combat Expertise, and Improved Unarmed Strike for the purposes of meeting the prerequisites of the various improved combat maneuver feats, as well as feats that require those improved combat maneuver feats as prerequisites."
So it should help meet the prerequisites for example: "Improved Trip" and "Greater Trip".
ie Prerequisites for "Greater Trip" should be: Dirty Fighting (Combat Expertise, Int 13) + Base Attack Bonus 6 + Improved Trip
I know that's not how it should code (i'm not a programmer) just my thought process. The bolded text is also missing from the feats description in PCGen.