Top-layer placement drawing for the Lenovo NM-B311 motherboard, an LCFC design, delivered as a PDF. The name does not give a revision or a laptop model. A sheet like this maps reference designators to their physical position on the component side, so a technician can find a part named in the schematic, reach nearby test points, or spot where a shorted capacitor sits. Open it in any PDF reader and search for designators. Check that the NM-B311 number and revision on the PCB match before working from it.
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 @pepeelectronica. 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.