Base64 URL Decoder & Opener v1.1.0
This is an addon for a niche usage. It decodes a base64 encoded (once or twice) URL and opens the URL in the tab to the right (in background). That's it. No other extraneous functions. You probably don't need this!
Usage: Select a base64 url and right click to invoke the context menu. You will see 2 options: Decode Once & Decode Twice. Select the right option based on how many times the url was encoded. The addon will decode and open it in the right tab.