Zip archive of 14.4 MB named SSRspeed, which matches an open-source tool for measuring proxy node speed rather than device firmware. The name states no hardware model, chip or version, so it is not something to write to a flash chip. It may have been grouped with router files because such tools are used alongside OpenWrt-based builds. Unpack it and read its documentation to confirm what it does. Keep it separate from genuine firmware images to avoid flashing the wrong file to a device.
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 @tamirkaran_chanel. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.
Back up your own chip before writing any dump, and match the full board number and revision. Flashing guide →