Spanish PDF titled Microelectrónica, 4.14 MB, with no device, brand or board named. It is likely training or course material covering microelectronics topics such as component identification, soldering of small packages, BGA work and board-level repair techniques. Such material builds the background needed to work on phone and laptop boards safely. Open it in any PDF viewer to see the chapters; it serves as general reference rather than documentation for a specific repair.
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.