/usr/share/plasma/plasmoids/org.kde.plasma.volume/ is in plasma-pa 4:5.5.5-0ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/plasma/plasmoids/org.kde.plasma.volume/contents/
/usr/share/plasma/plasmoids/org.kde.plasma.volume/contents/code/
/usr/share/plasma/plasmoids/org.kde.plasma.volume/contents/code/icon.js
/usr/share/plasma/plasmoids/org.kde.plasma.volume/contents/ui/
/usr/share/plasma/plasmoids/org.kde.plasma.volume/contents/ui/DeviceListItemBase.qml
/usr/share/plasma/plasmoids/org.kde.plasma.volume/contents/ui/Header.qml
/usr/share/plasma/plasmoids/org.kde.plasma.volume/contents/ui/ListItemBase.qml
/usr/share/plasma/plasmoids/org.kde.plasma.volume/contents/ui/RootItem2.qml
/usr/share/plasma/plasmoids/org.kde.plasma.volume/contents/ui/SinkInputListItem.qml
/usr/share/plasma/plasmoids/org.kde.plasma.volume/contents/ui/SinkListItem.qml
/usr/share/plasma/plasmoids/org.kde.plasma.volume/contents/ui/SourceListItem.qml
/usr/share/plasma/plasmoids/org.kde.plasma.volume/contents/ui/SourceOutputListItem.qml
/usr/share/plasma/plasmoids/org.kde.plasma.volume/contents/ui/StreamListItemBase.qml
/usr/share/plasma/plasmoids/org.kde.plasma.volume/contents/ui/VolumeIcon.qml
/usr/share/plasma/plasmoids/org.kde.plasma.volume/contents/ui/main.qml
/usr/share/plasma/plasmoids/org.kde.plasma.volume/metadata.desktop