A 3.19 MB ZIP archive covering two items labelled LB31B and LB36B, apparently grouped together because they are related variants. The name does not state the manufacturer, device type or whether the contents are firmware, dumps or documentation. Extract it and inspect the files before use. If flash images are inside, pick the one that matches the exact code on your unit, read and preserve the existing chip contents first with a programmer, and confirm that file size and memory capacity agree.
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 @gunvantrathore. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.