Small 669 KB PDF schematic tagged as Apple, named only 4 g, which most likely refers to an iPhone 4 generation device, though the name does not state the model clearly. No board number or revision is given, so compare the content with the logic board before use. A document like this helps when tracing power rails, checking charging and connector circuits or locating parts on a short. Given its size it may be a partial diagram or block section. Open it in any PDF viewer and confirm which device it actually covers.
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 @tamirat_moobile. 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.