Microchip PIC18F458 datasheet, a 3.95 MB PDF; the name also mentions 448, suggesting the PIC18F448 is covered in the same document. These flash microcontrollers include a CAN bus module, so they appear in automotive and industrial modules. The datasheet provides pinouts, CAN controller details, configuration bits and electrical specifications. When servicing, check supply, oscillator and CAN transceiver connections, and confirm which of the two parts is fitted before choosing a programmer profile.
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.