/usr/share/metview/etc/UiSpec.Breadcrumbs is in metview-data 4.8.0-4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | #------------------------------------
# Icon context menu
#------------------------------------
icon_menu,
        cmd		   = openInTab,
	label		   = 'Open in new tab'
	
icon_menu,
        cmd		   = openInWin,
	label		   = 'Open in new window'
	
icon_menu,
	type 		   = separator
	
icon_menu,
	cmd		   = bookmark,
	label		   = 'Add to &bookmarks',
        icon 		   = add_bookmark
 |