P0: Blocker WebEngine have absolutely no sound on Linux. It seems the configuration system has not been adjusted to the qtConfig() changes in qtbase and GYP_CONFIG always picks up use_pulseaudio=0 and use_alsa=0.
config/linux.pri
contains(QT_CONFIG, pulseaudio) {
GYP_CONFIG += use_pulseaudio=1
} else {
GYP_CONFIG += use_pulseaudio=0
}
contains(QT_CONFIG, alsa) {
GYP_CONFIG += use_alsa=1
} else {
GYP_CONFIG += use_alsa=0
}