zypper repo conf entry?

This is somewhat naive but can anyone explain the difference in the entry for the repos found in /etc/zypp/repos.d

the listing for each repo has:

name=whatever
baseurl=whatever
path=/
type=

and ‘type’ is either yast2 or rpm-md

what’s the diff between these in terms of method?

I would normally use Yast from the GUI menu for update or installs. I know that one can do a CLI method for either but I haven’t done so and wonder what the 'rpm-md means?

thanks

Standards/RPM metadata - openSUSE