Spanish-language course document on Android devices, supplied as a 424 KB PDF and filed under schematics although the title points to training material rather than a board diagram. The name gives no phone model, board number or Android version, so expect general content on the platform, its software and possibly basic service procedures. Useful as background reading for a technician new to smartphone repair; any PDF reader opens it, and model-specific work should still be checked against the proper service schematic for the exact board being repaired.
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 @canalesquematicos. 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.