Video Display Modes

Hi, can anyone help me out?

I am looking at OS development and would like to know where I can find out about the video modes in Linux. This Wikipedia page https://en.wikipedia.org/wiki/Extended_Graphics_Array#Standards lists lots of different video modes, I would like to know which ones Linux uses; this differs depending on your display manager, right?, what does Linux use before GNOME or KDE, that CLI still outputs in some sort of video mode right?

The table on that page shows resolutions, users can change there resolution dependent on there monitors and all that; but you don't need to implement a totally new specification just to change the resolution do you? does the video standard change when you change resolution?, surely not?

Thanks,

Jammmie999