PDF page from a smartphone schematic dealing with the LCD backlight circuit, labelled LCD_LIGHT, in a set of sectioned pages of about 4.77 MB; the model is not named. Expect the backlight driver IC, boost inductor, diode and the anode and cathode lines to the display connector. Technicians use it when the image is visible only under a torch, measuring the boost output and checking the coil and diode for failure. Confirm the page belongs to the same device as your board before swapping components.
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 @phoneSchematics. 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.