Microchip datasheet for the PIC16F87xA family of 8-bit flash microcontrollers, supplied as a 3.92 MB PDF. Expect pinout diagrams for each package, the memory organisation, special function registers, peripheral descriptions and electrical characteristics. Technicians use it to identify pin functions on a board, check supply and oscillator pins, find the ICSP programming pins and confirm the exact part marking before replacing or reprogramming a chip. Open it in any PDF reader and compare the suffix printed on the IC with the variants listed.
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.