I get this message in the logs: >>> Messages generated by process 145647 on 2021-08-25 18:44:52 CEST for package media-plugins/gst-plugins-mplex-1.18.4-r1: QA: configure QA: IUSE=orc is missing while plugin supports it QA: IUSE=introspection is missing while plugin supports it QA: IUSE=orc is missing while plugin supports it QA: IUSE=introspection is missing while plugin supports it Thanks
This looks like a bad QA check in eclass, making split plugin orc/introspection checks based on full tarball meson_options.
I had exactly same warnings in media-plugins/gst-plugins-{soup,taglib,v4l2}