Comment # 2 on bug 1231449 from Christophe Marin

(In reply to Aaron Puchert from comment #1)
> The package clang%{_sonum}-devel has indeed
> 
> Requires:       clang-tools >= %{version}

> I don't have an SP5 installation anymore, but I see clang17-devel without
> clang-tools in https://download.opensuse.org/update/leap/15.5/backports. So
> how did you get this to install?

Try `osc buildinfo -d home:krop:Qt6:Release qt6-tools 15.5 x86_64 | grep -E
'^added.*(llvm|clang)'`

There you can see that clang-tools isn't pulled when having `BuildRequires: 
clang17-devel` in your spec