Small zip archive of around 309 KB carrying only the Lenovo A510 model in its name, without saying what kind of documents are inside. It is likely service or schematic material for that phone, but inspect the contents before depending on it. Where it contains circuit diagrams, they serve for tracing supply rails, locating charging and display components and finding test points during diagnosis. Unpack it with 7-Zip or any zip utility, and confirm that the mainboard markings correspond to the drawings.
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 @SMART_PHONE_SCHEMATICS. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.