Archive labelled for the Xiaomi Mi 2S smartphone, packed as a 932 KB RAR, with no code name or document type mentioned. Extract it to confirm whether schematics, layout drawings or other service notes are inside. Material of this kind is used to trace power rails, check where a short to ground sits and identify test points and parts. The Mi 2S is a refresh of the Mi 2 and shares much of its design, but compare the board markings against the drawings before assuming the two are identical.
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 @mischematic. Enginerys does not host this file.
How to open a .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.