Compressed ZIP archive of 1.31 MB named only after the board number NM-A541, a Lenovo board by LCFC numbering. Nothing in the name says what is inside, whether a schematic, boardview or firmware dump, or which laptop model the board belongs to, so open it and check the contents first. LCFC is Lenovo's in-house design and manufacturing arm and uses the NM-xxxx pattern across IdeaPad and ThinkPad lines. Compare the number and revision printed on the PCB before trusting any data 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 @notebookschematic. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.