user.core.windows_and_tabs.tabs

tab (open | new)	app.tab_open()
tab (last | previous)	app.tab_previous()
tab next	app.tab_next()
tab close	Closes the current tab. Exists so that apps can implement their own delay before running tab_close() to handle repetitions better.
tab (reopen | restore)	app.tab_reopen()
go tab <number>	Jumps to the specified tab
go tab final	Jumps to the final tab
tab duplicate	Duplicates the current tab.