/usr/share/doc/libflamingo-java/api/org/pushingpixels/flamingo/internal/ui/ribbon/appmenu/ is in libflamingo-java-doc 5.0-1.
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/usr/share/doc/libflamingo-java/api/org/pushingpixels/flamingo/internal/ui/ribbon/appmenu/BasicRibbonApplicationMenuButtonUI.html
/usr/share/doc/libflamingo-java/api/org/pushingpixels/flamingo/internal/ui/ribbon/appmenu/BasicRibbonApplicationMenuPopupPanelUI.html
/usr/share/doc/libflamingo-java/api/org/pushingpixels/flamingo/internal/ui/ribbon/appmenu/CommandButtonLayoutManagerMenuTileLevel1.html
/usr/share/doc/libflamingo-java/api/org/pushingpixels/flamingo/internal/ui/ribbon/appmenu/CommandButtonLayoutManagerMenuTileLevel2.html
/usr/share/doc/libflamingo-java/api/org/pushingpixels/flamingo/internal/ui/ribbon/appmenu/JRibbonApplicationMenuButton.html
/usr/share/doc/libflamingo-java/api/org/pushingpixels/flamingo/internal/ui/ribbon/appmenu/JRibbonApplicationMenuPopupPanel.html
/usr/share/doc/libflamingo-java/api/org/pushingpixels/flamingo/internal/ui/ribbon/appmenu/JRibbonApplicationMenuPopupPanelSecondary.html
/usr/share/doc/libflamingo-java/api/org/pushingpixels/flamingo/internal/ui/ribbon/appmenu/package-frame.html
/usr/share/doc/libflamingo-java/api/org/pushingpixels/flamingo/internal/ui/ribbon/appmenu/package-summary.html
/usr/share/doc/libflamingo-java/api/org/pushingpixels/flamingo/internal/ui/ribbon/appmenu/package-tree.html