Firmware for the StarTrack SRT-5800 HD satellite receiver, dated 12 September 2018 and supplied as a RAR archive. Technicians use such a package to update the box or recover it after software corruption, loading it by USB or writing it straight to the flash memory with a programmer. Sister models SRT-5700 and SRT-5900 have builds of the same date and size, so be sure the target unit is the 5800 version, and keep a dump of the current firmware before flashing.
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 @tvsoftwareworld. 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.
7-ZipWinRARThe Unarchiver (macOS)