it's linked but the product list doesn't show it

Adrian, any idea why 15 is not shown in the product xml?

Not yet supported xml tag in index parser ... fixed now.

Btw, you have a broken product definition in 000package-groups container:

osc api '/source/openSUSE:Leap:15.0/000package-groups?view=products'¶

Server returned an error: HTTP Error 400: /srv/obs/sources/000package-groups/-dvd.group No such file or directory
/srv/obs/sources/000package-groups/-dvd.group: No such file or directory

listing works now, thanks