Service archive for the Xiaomi Mi 9T, which was also sold as the Redmi K20; the name lists both. The ZIP is 1.45 MB, and the name does not specify whether it contains schematics, placement diagrams or another document. For phone repair such files are used to locate components, test points and power lines around the PMIC, charging IC and connectors. Check that the board version referenced inside matches your unit, because variant-specific changes can affect part placement.
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 @Schematics_Mobile. Enginerys does not host this file.
All sources (22)
The same file was posted more than once. If one link is dead, try the next.
How to open a .zip file
Compressed archive that every operating system opens without extra software.