When I search for packages on software.opensuse.org, I only see options for tumbleweed and 15.2, not for 15.3. I have this problem for a while, when it worked for some time, but now for several weeks, I do not see 15.3. The workaround is to search a package and then install it from yast. When I have to add a repo, I can take the 15.2 repo URL and edit it to 15.3, when things work. The packages are there but not showing. Does somebody else have this problem?
Yes. Everyone. The fix (Fix Leap 15.3 search by agraul · Pull Request #1065 · openSUSE/software-o-o · GitHub) was merged and it even worked for a short time, then it became broken again.