Where do you got the tarball from ? If it's based on some git revision it probably makes sense to use a _service file with tar_scm to create the tarball.

The original source package was taken from fldigi git tree on sf. Here is the link: https://sourceforge.net/code-snapshots/git/f/fl/fldigi/flxmlrpc.git/fldigi-flxmlrpc-fd52fdeb8a091a39dc472bb5ef6c27e32498d749.zip. I renamed top directory and repackaged to tar.gz to make it compatible with the specfile. Is it possible to do the dir rename with obs _service?

Instead of messing with the zip-file you could checkout the mentioned revision from the git repository via tar_scm/obs_scm. See https://build.opensuse.org/package/view_file/home:mnhauke:branches:home:wkazubski:test:science/flxmlrpc/_service?expand=1

@Dmitry_R, @mnhauke, @pluskalm: review reminder