A schematic diagram. Shared as “SM-A03 BACK_CAMERA_48MP_WIDE.pdf” — a .pdf file, 2.81 MB.
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 @phoneSchematics. 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.