https://manpages.ubuntu.com/manpages/xenial/man3/XmLabelGadget.3.html
Ubuntu Manpage: XmLabelGadget - The LabelGadget widget class "XmLabelGadget" "widget class"...
The LabelGadget widget class "XmLabelGadget" "widget class" "LabelGadget"
ubuntumanpagewidgetclass