Compressed RAR archive labelled only with the phone model Y9 2018, a name used by Huawei for its Y9 2018 handset, though the file name itself does not say what the archive holds. At just over 1 MB it most likely contains a compact schematic set, a block diagram or a few service pages rather than full firmware. Extract it with WinRAR or 7-Zip and inspect the contents before relying on them, and confirm that the board markings inside match the phone on your bench, since Y-series models share names across years and variants.
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 @uzb4422. 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.