PDF schematic labelled Note 8 Pro, 1.44 MB, numbered (2) and presumably part of a set alongside a smaller companion file. The name most likely refers to a Redmi Note 8 Pro, though no brand is given. Each part probably covers different sections of the board, so keep both together for complete coverage of power, charging, display and RF areas. Use it to trace rails and locate components when diagnosing shorts or no-boot faults, and confirm the board in front of you matches before relying on 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 @uzb4422. 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.