Description of problem: Software application installer does not find Ardour4, only the v2 legacy version Maybe there is some metadata missing in the ardour4 package that Software uses to find "end user applications" from the repository?
The ardour4 package is obsoleted by ardour5. Both contain an appdata file (the ardour4 one is missing a timestamp in the release tag, however the ardour5 one validates correctly) and I'm not aware of anything else that needs to be done to show up in GNOME Software. I'll change the component to gnome-software for now to get some input from their side.
This turned out to be a bug in the appstream builder. Should be fixed with https://github.com/hughsie/appstream-glib/pull/142
appstream-data-25-11.fc25 has been submitted as an update to Fedora 25. https://bodhi.fedoraproject.org/updates/FEDORA-2016-88447eec2c
appstream-data-25-11.fc25 has been pushed to the Fedora 25 testing repository. If problems still persist, please make note of it in this bug report. See https://fedoraproject.org/wiki/QA:Updates_Testing for instructions on how to install test updates. You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2016-88447eec2c
appstream-data-25-11.fc25 has been pushed to the Fedora 25 stable repository. If problems still persist, please make note of it in this bug report.