Schematic for the Xiaomi Redmi Note 4X, supplied as a 6.41 MB PDF; the trailing (1) in the name only marks a duplicate copy. Technicians open it in a PDF viewer to follow PMIC outputs, the battery and charging path, and the display and camera connector lines, and to identify components behind boot or power faults. The Redmi Note 4X was sold with different chipsets in different markets, so check the board markings and the chipset on your unit against the document before relying on any 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 @smart_repair_phone. Enginerys does not host this file.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.