Whilst Orion Browser already has the ability to clear all your tabs with two taps: Orion > Long press on the "Tabs" icon denoted by two squares > Select Close All Tabs, compared with DuckDuckGo's fire button, it becomes cumbersome when you also want to delete all history and cookies: Meatballs Menu > History > Clear. You can also: Settings > Data Management > Clear History and Website Data, but this option doesn't clear all tabs either.
The Fire Button is a DuckDuckGo browser feature that clears all tabs and data in less than a second. It's conveniently placed next to the address bar and tab manager. When used, the Fire Button clears everything, including cookies, and can be done at any time while browsing.
Adding another button, in this case "Clear all tabs, history and cookies" in Orion Browser iOS can perhaps become a bit tricky due to the lack of space; increasing the functionality in the long press tab switcher icon with "Delete all tabs, history and cookies" might not be.
The Fire Button: