EV3 had a microsd slot and usb ports. You can boot Debian on it and connect it to WiFi, which made it pretty wide open. https://www.ev3dev.org/
The kit that replaced EV3 is also really great. I have both and mostly use the newer one because even though it can't boot Linux or connect to WiFi, it can be programmed from an iPad using a scratch interface, and the programs can be saved to the device and run without having to use any other device. This makes it really easy to quickly make a robot to perform a simple task like pressing a series of physical buttons in a timed loop, like for farming Xbox game currency or whatever. EG https://youtu.be/otAQqtLifCU