x11-wm/lumina-0.8.8_p1 should depend on dev-qt/qtmultimedia:5[widgets] and dev-qt/qtsvg:5 (in DEPEND and RDEPEND). In unpacked source archive: $ grep -E "(multimediawidgets|svg)" **/*.pr[io] libLumina/libLumina.pro:greaterThan(QT_MAJOR_VERSION, 4): QT += widgets x11extras multimedia concurrent svg lumina-desktop/lumina-desktop.pro:greaterThan(QT_MAJOR_VERSION, 4): QT += widgets x11extras multimedia concurrent svg lumina-fm/lumina-fm.pro:greaterThan(QT_MAJOR_VERSION, 4): QT += widgets multimedia multimediawidgets network concurrent svg The only thing from dev-qt/linguist-tools:5 which is used here is lrelease and it is most likely used only at build time. So dependency on dev-qt/linguist-tools:5 should be only in DEPEND and not in RDEPEND. Currently it is also in RDEPEND due to 'RDEPEND="${DEPEND}'.
Ah, thanks for the heads-up; these dependencies where missing from the upstream documentation and I had them installed already which is why I missed them. I'm setting up a container with a minimal gentoo installation to test packages as per idella4 and wraeth's recommendations. In the meantime, I've created a pull request here: https://github.com/gentoo/gentoo/pull/1151
*** Bug 578348 has been marked as a duplicate of this bug. ***
The pr is ready for testing and was already tested succesfully by Sam!
i committed this and tested. its fine. i'm going to remove the mask in a sec. thanks for your work!