Basically, just a GTA4 pirate rip and modded and sold on actual disks.
There are several, and they are hard to find online because any uploads of it probably don't exist anywhere anymore, and were already rare due to aforementioned disks.
Some of them are so regional and probably made by one person, the only way to find one is to get a computer HDD with it installed.
Pakistani flags everywhere, reskinned character and NPCs, Pakistani songs, story characters replaced by famous IRL people, including some known mafia lol. Some original missions and reduxed interactions and updated story. Also lots of military additions.
Some were also themed after a specific city like Karachi or Lahore.
I'm sure Pakistan wasn't the only country since I've heard there were hilarious and great modded bootlegs in other countries as well.