/usr/include/phonon/Phonon/ is in libphonon-dev 4:4.10.0-2.
This file is owned by root:root, with mode 0o755.
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/usr/include/phonon/Phonon/AbstractAudioOutput
/usr/include/phonon/Phonon/AbstractMediaStream
/usr/include/phonon/Phonon/AbstractVideoOutput
/usr/include/phonon/Phonon/AddonInterface
/usr/include/phonon/Phonon/AudioOutput
/usr/include/phonon/Phonon/AudioOutputDevice
/usr/include/phonon/Phonon/AudioOutputDeviceModel
/usr/include/phonon/Phonon/AudioOutputInterface
/usr/include/phonon/Phonon/BackendCapabilities
/usr/include/phonon/Phonon/BackendInterface
/usr/include/phonon/Phonon/Effect
/usr/include/phonon/Phonon/EffectDescription
/usr/include/phonon/Phonon/EffectDescriptionModel
/usr/include/phonon/Phonon/EffectInterface
/usr/include/phonon/Phonon/EffectParameter
/usr/include/phonon/Phonon/EffectWidget
/usr/include/phonon/Phonon/Global
/usr/include/phonon/Phonon/MediaController
/usr/include/phonon/Phonon/MediaNode
/usr/include/phonon/Phonon/MediaObject
/usr/include/phonon/Phonon/MediaObjectInterface
/usr/include/phonon/Phonon/MediaSource
/usr/include/phonon/Phonon/ObjectDescription
/usr/include/phonon/Phonon/ObjectDescriptionModel
/usr/include/phonon/Phonon/Path
/usr/include/phonon/Phonon/PlatformPlugin
/usr/include/phonon/Phonon/SeekSlider
/usr/include/phonon/Phonon/StreamInterface
/usr/include/phonon/Phonon/VideoPlayer
/usr/include/phonon/Phonon/VideoWidget
/usr/include/phonon/Phonon/VideoWidgetInterface
/usr/include/phonon/Phonon/VolumeFaderEffect
/usr/include/phonon/Phonon/VolumeFaderInterface
/usr/include/phonon/Phonon/VolumeSlider