SM4450 processor schematic in PDF form, 1.28 MB; the name gives no phone model, board number or revision. It shows how the SoC connects to power management, memory, storage and peripheral buses. Repair technicians use such drawings to identify expected voltages, follow clock and reset lines, and pin down shorts on rails feeding the CPU. Treat it as a generic reference and confirm that net names and designators correspond to your handset before relying on any measurement.
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.