Close New Duplicate Tabs от Sunfur

Stop accidentally opening the same webpage twice and cluttering your tabs bar!

Automatically detects and closes a newly created tab if its URL is already open in another tab. It silently redirects your focus to the existing tab, saving you time, reducing memory usage, and keeping your tab bar clean.

Unlike other extensions with similar functionality, this one only works on newly created tabs, meaning that you wont lose tabs with history.