PDF datasheet of about 155 KB for display module PG320240ERF-XNN-H-A1, where A1 appears to be the document or hardware revision. The core code indicates a 320 x 240 dot graphic LCD. Typical sections cover pin functions, electrical and optical characteristics, timing and mechanical outline. Technicians use it to confirm interface wiring, LCD bias and backlight requirements. Revisions can change details, so check that the marking on your module corresponds to the A1 version described.
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.