There are usually many "Unknown" devices/brands due to the inability to detect the device/brand of a desktop computer. We can't eliminate all the unknowns, but we can try to reduce their number by:

• Introduce a "Generic Desktop" device type and device brand that is used if the device is a desktop. Since most of the unknowns are like desktops, this should put a big dent in the number.
• For brands, if the OS == Mac, assume the brand is Apple.

CC @mattab @sgiehl @tsteur