A general PIC reference document in PDF form, 869 KB in size. The name gives only a generic book title and no specific device, author or edition, so its exact contents are unclear until opened. Such material typically explains PIC microcontroller architecture, the instruction set, ports and programming basics, which helps a technician understand firmware behaviour and circuits around these chips. For pinouts and electrical limits of a specific controller, rely on the dedicated datasheet that matches the marking on the part.
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 @datasheet. 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.