Here x32 and x64 bit plugins for open umod files via 7-zip file manager.
Install: drop dll into Codecs dir in 7-zip folder, e.g. C:\Program Files\7-Zip\Codecs
Features:
Check CRC, check Header size - if something fail you will see that in information window.
Show CRC, file size, special flags (as attributes), version.
limitation: only read UMOD, not write.