"Programmable buttons" refers to buttons on a device that can be customized or set up to perform specific functions according to the user's preference. Full definition
The tablet also has a couple of programmable buttons on the front, plus an 8 - megapixel rear camera and a 1080p front - facing camera. (zdnet.com)
It also has an extra programmable button on the left side just above the volume rocker that defaults to the Samsung Activity app, but you could reset it to be a camera button or to perform one of many other duties. (androidheadlines.com)
It's a good product with a lot of programmable buttons for all your flight sim needs and a responsive stick and great compatibility options. (wolfsgamingblog.com)