Before you burn your CD/DVD images, you should check the files for errors. A file named <some>.iso.sha256 is available. This file contains hashes for the corresponding ISO image that is available from that download location.
This [openSUSE-Leap-15.4-DVD-x86_64-Build6.1-Media.iso] is probably the first refresh of installation images that was planned, but I am not sure why it landed in “appliances”.
I may have lost some brain cells. Can I clarify the situation?
I have already downloaded a file labeled Updated Offline Image with the name openSUSE-Leap-15.4-DVD-x86_64-Build6.1-Media.iso. There seems to be no checksum for this, User hui tells me to
Click on the small black triangle next to the word "Download" and you will find the checksums to download...
when I do this nothing happens. It looks like you are suggesting I should download release 243.2 then update it to (supposedly) version 6.1. This sounds somewhat retrogressive to me, but I will do it if necessary.
I just tried that. When I click the triangle, I get a menu which includes “Checksum” as an option. So I clicked on “Checksum”. This was in “firefox” and it looked as if nothing happened. However, when I checked the usual download place, I saw that a 108 byte file had been downloaded, with the checksum.