Mobile Content Scale Factor

Hello, when i input 1 in MobileContentScaleFactor i get 1280x720 resolution, when i input 0 in MobileContentScaleFactor i get native resolution of the device, but when i input 0.6 i get 0.6 scale from 1280x720 or i get 0.6 scale from native resolution of the device ?
Example we have a device with the native resolution 1920 x 1080, so if i will input 0.6 resolution will be taken from 1920 x 1080 and i will get 1152 x 648 or resolution will be taken from 1280x720 and i will get 768 x 432. I hope you understand me