Generic PDF named only as an update, 1.35 MB in size, with no model, brand or board number given. Its subject cannot be determined from the name, so open it to identify what it covers before filing it with a particular device. If it is a schematic, note the board number and revision on its title block and compare them with the PCB in hand. Schematics help a technician follow power rails, locate components by designator and confirm the values of parts that have burned.
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 @SCHEMATICWORLD. 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.