It had been in the works for a while, but now it has formally been adopted. From the article:
The regulation provides that by 2027 portable batteries incorporated into appliances should be removable and replaceable by the end-user, leaving sufficient time for operators to adapt the design of their products to this requirement.
Probably they would make the battery removable from the bottom with some screw on the bottom. At least that’s how I’d do it if I were them considering the batteries are linear anyway and are usually in the parts sticking down.