A PDF datasheet for the PC1602LRS-JSO-K module, a sixteen-character, two-line LCD as indicated by 1602, with JSO-K denoting the specific build. Contents typically cover connector pin assignment, absolute and operating ratings, backlight figures, interface timing and outline dimensions. On repair jobs it guides measurements of logic supply, contrast voltage and backlight current, and helps pick a compatible replacement. Always compare the printed part code on the module, since close variants exist.
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.