PDF service document labelled 32LJ500B, a model code in LG's television numbering style, which suggests a 32-inch LCD TV, though the name gives no brand. At 4.51 MB it likely covers the main board, power supply and backlight circuitry along with block diagrams. Technicians use such material to trace standby and backlight voltages, find test points and identify failed parts on a TV with no picture or no power. Check the chassis and board labels inside the set before relying on values, since panel and board variants differ.
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 @pdf_servicemanual. 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.