What is mmb on keyboard?

"MMB" on a keyboard stands for "Middle Mouse Button." It is typically the third button on a standard computer mouse, situated between the left and right buttons. The middle mouse button is often used for functions such as opening links in a new tab, scrolling by clicking and dragging, and rotating objects in 3D software. Some mice also feature a scroll wheel that can be clicked to function as the middle mouse button. The middle mouse button can be a useful tool for navigating and interacting with content on a computer.