Schematic in PDF, 1.68 MB, for the SM6125 processor with an SM61 family tag; the phone model and board number are absent from the name. Pages like these document SoC power domains, PMIC connections, memory buses and clock circuitry. A technician can use them to check which rails should be present, find test points and trace a short around the processor. Cross-check reference designators against the actual handset, as boards built around the same chip differ.
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 @mischematic. 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.
Any PDF readerSumatraPDFFirefox / ChromeFlexBV (links PDF to boardview)