there is something like this in some frameworks:
```
%if 0%{?docs}
%package doc
Summary: API documentation for %{name}
BuildRequires: doxygen
BuildRequires: qt5-qdoc
BuildRequires: qt5-qhelpgenerator
BuildRequires: qt5-qtbase-doc
BuildRequires: make
Requires: kf5-filesystem
BuildArch: noarch
%description doc
%{summary}.
%endif
```

Is that what you meant?