Zip archive of about 1.04 MB named for the Xiaomi Mi CC9 Pro smartphone. The name does not say what is inside, but archives of this size in a repair index usually hold a schematic or a component-placement diagram as PDF or image files. Technicians use such material to trace power rails, locate PMIC and charging circuitry, find test points and follow signal paths when diagnosing shorts or no-power faults. Unpack and confirm the contents, and compare the board markings on the phone before relying on any layout inside.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @esquematicosparatodos. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.