Bottom-side placement drawing in PDF for the Xiaomi M1s board at the P3 build stage. It shows where components and their designators sit on the underside, so a part found in the schematic can be located quickly on the real board. Technicians use these sheets to find test points, spot candidates for a short and check that the correct component is being replaced. Pair it with the M1s schematic and top-side file, and check that the board matches the P3 stage before relying on the positions.
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 @mobileschematicshub. 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.