Need some help with SDL_WINDOWS_DPI_SCALING

In the comments of SDL_WINDOWS_DPI_SCALING, it says the following secondarily:

  • “1” - SDL coordinates are in DPI-scaled points. Automatically resize windows as needed on
    displays with non-100% scale factors.

Can anyone explain to me what this means? What are SDL coordinates and what does that include, does that include the mouse position we get from SDL functions? Or is that only for the size of the window?

I would like to note that if the mouse position is scaled by SDL automatically, it does not do that to me.

Any help is appreciated.