ZIP archive for the Xiaomi Mi 2, 1.82 MB, with a name that states only the model and gives no document type or board revision. Its size is consistent with service documents such as schematic pages rather than a full firmware package, but the actual contents should be checked after unpacking. If diagrams are inside, they help a technician follow the battery and charging circuitry, trace PMIC rails, read connector pinouts and locate the part behind a fault. Confirm the board markings on the handset before trusting component values.
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.