WARNING: The following contains minor spoilers for Batman #106 by James Tynion IV, Jorge Jimenez, Tomeu Morey and Clayton Cowles, and from the Batman Urban Legends #3 story "Cheer," by Chip Zdarsky, Eddy Barrows and Eber Ferreira.
The Batcave is arguably the most famous superhero hideout in the known universe. Batman is synonymous with his Wayne Manor and the sprawling Batcave below it, carved out of limestone and bedrock, but things can't always stay the same. During the Joker War, Joker stole most of Bruce Wayne's fortune. This was one of the main pillars of his attack on Gotham, and it's how he funded the apocalyptic chaos that filled the streets. However, Catwoman was able to steal the Wayne fortune back, but she couldn't give it back to Bruce or risk his ruining his secret identity. So now that Lucius Fox is the richest man in Gotham, Batman can't rely on an infinite amount of resources to fight crime. He's adapted a more low-key approach, and one of the first things to go was his lavish and advanced Batcaves of old. His new primary cave is simply called The Garage.
Lucius Fox informed Batman that it might be better for him to relinquish his fortune to keep anyone from peering into Wayne Industries' prior affairs. After the Joker War, Wayne Enterprises was trying to rebrand and separate themselves from the Wayne name. Batman decided leaving his fortune in Fox's hands would be best to keep any of the board members from peering too deep into Wayne Enterprises's extracurricular activities making A.I.-powered Batmobiles and all kinds of other weaponry for the Batman. Batman was forced to relinquish most of his tech, but it came at a time when Batman was already in the middle of a crimefighting paradigm shift.
The Garage is one of his new primary Batcaves in Gotham, and it represents Batman's paradigm shift in a beautiful way. Long gone are the 100-inch computer screens, forensic labs and hangars filled with all kinds of Bat-themed vehicles. The Garage is as low-key as it gets and is more like one of Batman's many safe houses that operated alongside the main Batcave for years in Gotham. These safe houses were stripped-down versions of his Batcave that allowed him to restock and recoup in between battles. The Garage seems to be his main hideout because we see him there in Batman #106 by James Tynion IV, Jorge Jimenez, Tomeu Morey and Clayton Cowles. Bruce also mentions the Garage in "Cheer," from Batman Urban Legends #3 by Chip Zdarsky, Eddy Barrows and Eber Ferreira.
The Garage is a bare-bones setup from what we've seen. This is where Batman comes between patrols to research his cases and chill after work with a few beers in front of his modest workstation. His new computer probably lacks the power of his former supercomputer forcing Batman to be more hands-on with his detective work. The only remaining trinket from Batman's rogues gallery is a giant Joker card laying on the floor like an eccentric rug.
The Garage represents the old-school hands-on approach Batman had to adopt in the wake of the Joker War. The Garage is the home base for a more grounded operation that will help Batman keep tabs on the heartbeat of the city. Batman is even going back to the basics for his training methods, which consist of a heavy bag and sparring sessions with Ghost Maker. Gotham City is changing faster than it ever has, and Batman is changing with it to make sure he doesn't lose touch with the city during uncertain times.