List of Keys (Keyboard, Mouse and Joystick)
LButton The left mouse button when used with Send, but the primary mouse button when used with hotkeys. In other words, if the user has swapped the buttons via system settings, LButton:: is physically activated by clicking the right mouse button, but Send {LButton} performs the same as physically clicking the left button.
https://www.autohotkey.com/docs/KeyList.htm#mouse-general