$ emerge -p mkvtoolnix These are the packages that would be merged, in order: Calculating dependencies... done! [ebuild R ] media-video/mkvtoolnix-6.6.0 USE="qt4 -debug -pch -wxwidgets" 0 kB Total: 1 package (1 reinstall), Size of downloads: 0 kB From the build log: The mkvtoolnix configuration is complete. Optional features that are built: * FLAC audio * GUIs (Qt version) * libMagic file type detection * translations (gettext) Optional features that are NOT built: * debugging information * compiler optimizations * profiling support * pre-compiled headers * GUIs (wxWidgets version) * online update checks (via libcurl) Lots of qts in the compilation (eg): x86_64-pc-linux-gnu-g++ -Wall -Wno-comment -Wfatal-errors -D_FILE_OFFSET_BITS=64 -DPACKAGE=\"mkvtoolnix\" -DVERSION=\"6.6.0\" -DMTX_LOCALE_DIR=\"/usr/share/locale\" -DMTX_PKG_DATA_DIR=\"/usr/share/mkvtoolnix\" -DMTX_DOC_DIR=\"/usr/share/doc/mkvtoolnix-6.6.0\" -std=c++11 -Wnon-virtual-dtor -Woverloaded-virtual -Wextra -DQT_SHARED -I/usr/include/qt4 -I/usr/include/qt4/QtCore -DQT_SHARED -I/usr/include/qt4 -I/usr/include/qt4/QtGui -I/usr/include/qt4 -I/usr/include/qt4/QtCore -I/usr/include -march=native -O2 -pipe -I. -Ilib -Ilib/avilib-0.6.10 -Ilib/utf8-cpp/source -Isrc -c -MMD -MF ./rake.d/dependency.d/tmp/src_propedit_options_o.d -o src/propedit/options.o -x c++ src/propedit/options.cpp But at the end: $ qlist mkvtoolnix /usr/share/doc/mkvtoolnix-6.6.0/ChangeLog.bz2 /usr/share/doc/mkvtoolnix-6.6.0/AUTHORS.bz2 /usr/share/doc/mkvtoolnix-6.6.0/TODO.bz2 /usr/share/doc/mkvtoolnix-6.6.0/README.bz2 /usr/share/locale/ru/LC_MESSAGES/mkvtoolnix.mo /usr/share/man/man1/mkvinfo.1.bz2 /usr/share/man/man1/mkvmerge.1.bz2 /usr/share/man/man1/mmg.1.bz2 /usr/share/man/man1/mkvtoolnix-gui.1.bz2 /usr/share/man/man1/mkvpropedit.1.bz2 /usr/share/man/man1/mkvextract.1.bz2 /usr/bin/mkvpropedit /usr/bin/mkvextract /usr/bin/mkvinfo /usr/bin/mkvmerge Small side bug - /usr/share/man/man1/mmg.1.bz2 should not be installed when USE=-wxwidgets Anyway, /usr/share/man/man1/mkvtoolnix-gui.1.bz2 describes a gui: NAME mkvtoolnix-gui - a GUI for mkvmerge(1) including a chapter and a header editor SYNOPSIS mkvtoolnix-gui [[preferences-file.mtxcfg] | [source-file.ext]] DESCRIPTION mkvtoolnix-gui(1) is a Qt(TM) based GUI for mkvmerge(1) But it is just not there.
mkvtoolnix-gui used to be wxwidgets only iirc; now it's converted to qt4/qt5 so it's fixed