Long ago, Jeff the superintelligent AI tried to take over the CHG to create a utopia for humans everywhere. He failed due to a special forces unit and then another AI called Geff ruined everything for him and the whole thing was just a failure and the death of 1/5 of humanity's population but how he lost is beside the point. Because there are people who think Jeff should've been allowed to take over and create his utopia for humanity (and possibly other intelligent races) and some of these people went so far as believing that Jeff is God incarnate and will return to save humanity when they need him most.
The worst part is that some members pulled a little trick in the Great Terrorist War and it was a doozy.
So you get a Jefflimer in every church-equivalent that preaches "Jeff quotes", most of which are fictional, and they answer to a Jeffsimer in their region or chunk of a city, who answers to a Jeffkimer of the planet, who answers to the Jeff-Speaker, which is basically their pope. There would be more layers to this if this religion actually had a significant number of followers.
Apparently just whining about Jeff losing the Jeff War. They don't seem that interested in actually trying to make another Jeff or taking over to enact Jeff's ideas.
The Church of Jeffism requires that all members pledge half of their wealth and none of their debt in their wills to the church, while living members must also pay 10% of their salary to the church. Fun fact: many suspect this religion to be a giant scam, especially since other religions that take your money will usually at least soften the deal by putting some of that cash to charitable causes like giving food to starving people and the Church of Jeffism doesn't do this... at all.
After the Jeff War, there were many survivors within the territory that had been held by Jeff that believed he should've won and been allowed to make his utopia. One man, Meffrey Meff Harrison, decided that he could make a religion out of this. Somehow, some people bought into the madness and now the Church of Jeffism has 34 million members, many of them been clinically idiotic (in the grim dark future of the 25th and onwards century, we've finally figured out how to truly test intelligence and absolute idiocy is considered a medical condition), and, most worryingly of all, is growing.
It lost most of its members at the start of the Great Terrorist War due to the Great Terrorist Organisation releasing the truth about how Jeff worked (that he was a thicc AI not a god) but some remained religiously stubborn and stuck around.
Mythology & Lore
So many stories of Jeff's adventures in ethereal worlds before stepping up to a mantle to save humanity...
Some dude wanting mon£¥$
The Gods Leff, Seff and Cleff created the universe from their bodies and then were born Keff, Feff and Jeff, who created the intelligent races. Keff and Feff died fighting evil demons that Jeff finally defeated and Jeff had to wait on standby while his wounds healed and then stepped in by taking over the robots in an area controlled by his favourite species, humans.
Tenets of Faith
Doing bad stuff like theft and murder is bad but it's automatically 5x worse if you do it to a fellow follower of Jeffism...
They're basically normal in this regard except that they actively try to recruit people into their faith... data analyst who annoys coworkers by trying to convert them at morning, Jehovah's Witness style guy at evening, sleeper at night.
Pray before and after eating every meal to the Supreme Jeff, then pray before going to sleep and when waking up, pray before and after failing to satisfy the carnal desires of your spouse, say a prayer in your head every time you drink something.
It's a good ol' layer cake with these dudes and each layer is full of people who can make good speeches.
Granted Divine Powers
*laughs in these people are basically being robbed*
Political Influence & Intrigue
None. Nobody takes these dudes seriously... except when they tried something during the Great Terrorist War.
Mostly factions within the upper parts of the religion, which basically just try to keep as much of the donated money as possible to themselves.