Schematic in PDF format for the Samsung SM-M315F, the Galaxy M31, at 3.28 MB. A file of this size probably contains several circuit sheets, such as block diagrams, power management, charging and interface sections. Technicians use it to follow voltage rails from the PMIC, check connector pins and find parts on a shorted line before injecting voltage or replacing a component. Any PDF viewer opens it, and text search speeds up locating references. Check the model label first, because the M315F and M317F are separate boards.
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.