Duplicate Tabs Closer detects and closes duplicate tabs. "On duplicate tab detected" options:

Close tab automatically: automatically closes the detected duplicate tab.
Do nothing: monitor tabs and update the badge icon to indicate the number of duplicate tabs detected.

"On remaining tab" options (used with "Close tab automatically):

Do nothing (default): nothing is done after the duplicate tab is closed.
Activate: once the duplicate tab is closed, the remaining tab is activated.
Apply opening tab behavior: once the duplicate tab is closed, depending on the default tab behavior, the remaining tab will be moved to the position of the closed tab and activated if needed.

"Whiltelist" options (used with "Close tab automatically):

List of urls to not close automatically. Duplicate tabs detected will be notified in badge. Wildcards is supported. "Priority" options (used with "Close tab automatically" mode and "Close all duplicate tabs" button):

Keep older tab (default): Keep the already existing tab.
Keep older tab and reload: Keep the already existing tab and reload it.
Keep newer tab: Keep the newer tab.
Keep tab with https (default on): Ignore the scheme part during comparison and keep the tab with the https scheme.
Keep pinned tab (default on): Keep the pinned tab.

"Filters" options:

Ignore case in URL (default off)
Ignore 'www' in URL domain name (default off)
Ignore hash part in URL (default off)
Ignore search part in URL (default off)
Ignore path part in URL (default off)
Compare with title (default off)

"Scope" options:

Container in active window: only closes/displays duplicate tabs that belong to a same container in the active window.
Container in all windows: only closes/displays duplicate tabs that belong to a same container in all windows.
Active window (default): only closes/displays duplicate tabs that belong to the active window.
All window: closes/displays duplicate tabs for all windows.

"Customization" options: (only accessible from the page Options - opened from extension popup panel by clicking on top right icon or by opening the Extensions panel and select extension's options )

Duplicate tabs badge color: Set the badge color for duplicate tabs.
No duplicate tab badge color: Set the badge color for no duplicate tabs
Show badge if no duplicate tab: Show badge with value 0 if no duplicate tabs

Hotkey:

Alt+Shift+W to close all duplicate tabs (this could be configured in the options in future version)