1. Rules on farming, aka that you are not supposed to take more than one big item per week from NPC gangers. It's especially hard to pass down this one icly when you have a lot of people RPing, and sometimes doing, the very opposite, often beating up and looting/stripping gangers. It makes it pretty hard to convey to players, as a player, why we shouldn't do that with that background.
2. Explain that all business in red are very much shaken-down by gangs and pay tolls for the protection. This is something that will probably be obvious to our characters icly, but to find out that this is the case as a player is problematic. You honestly can even be in a gang and not know about the behind-the-scenes tax that businesses pay to gangs. And this has a significant impact on a lot of IC stuff, so I think having this as common-knowledge helpfile would help with this.
I was going to add one more point, but as I wrote it, it grew big, so likely should be its own thread. Hopefully having a handy help file like that will make for less awkward RP of trying to explain why farming NPC gangers is bad, even though it's what a lot of people expect to be the core of ganger life, and seems like an easy cash intake.