Datasheet for the PE12864-004 module, a 261 KB PDF covering what is most likely a 128 x 64 dot graphic LCD in its 004 version. Expect pin assignment, absolute maximum ratings, electrical characteristics, interface timing and mechanical drawing. Technicians reach for such a sheet to locate supply and contrast pins, check the controller interface with a scope and confirm fit for a replacement. Make sure the version number on the panel matches 004 before using its values.
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 @acodis_lcd_datasheets_EDID. 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.