Founder/CEO of DuckDuckGo here. This title implies we are injecting third-party advertising into web forms, which is not the case. (Edit: that last sentence is now moot since the title has been updated. Thank you.)
This is part of the onboarding for our optional DuckDuckGo Email Protection feature that comes with the extension. (Note if you just use our private search engine, you do not need our extension at all.) The feature generates email aliases for you on sign up forms (so you don't give out your real email address), which then forwards to your regular inbox with email trackers removed in the process: https://spreadprivacy.com/protect-your-inbox-with-duckduckgo.... It is mentioned in the add-on description as one of the extension's primary features, e.g., at https://addons.mozilla.org/en-US/firefox/addon/duckduckgo-fo....
(x-posting part of another comment here for context on this feature: Popping up a level, the goal of our product is to be the "easy button" for privacy, and email protection is a big part of it, since as we (and others) have gotten much better at web tracking protection (e.g., see https://help.duckduckgo.com/duckduckgo-help-pages/privacy/we...), unscrupulous actors have done more and more email tracking, using your email address as a unique identifier to track you across sites and putting email trackers within emails to do similar.)
Update: I am listening to the feedback presented here, though please know there is a whole team of people working on this feature, trying to bring needed email protection to our mainstream user base. Email protection as a concept is hard for people to understand and the team felt that this in-context onboarding was the best way to explain it. However, we will now revisit this given the feedback.
This is part of the onboarding for our optional DuckDuckGo Email Protection feature that comes with the extension. (Note if you just use our private search engine, you do not need our extension at all.) The feature generates email aliases for you on sign up forms (so you don't give out your real email address), which then forwards to your regular inbox with email trackers removed in the process: https://spreadprivacy.com/protect-your-inbox-with-duckduckgo.... It is mentioned in the add-on description as one of the extension's primary features, e.g., at https://addons.mozilla.org/en-US/firefox/addon/duckduckgo-fo....
(x-posting part of another comment here for context on this feature: Popping up a level, the goal of our product is to be the "easy button" for privacy, and email protection is a big part of it, since as we (and others) have gotten much better at web tracking protection (e.g., see https://help.duckduckgo.com/duckduckgo-help-pages/privacy/we...), unscrupulous actors have done more and more email tracking, using your email address as a unique identifier to track you across sites and putting email trackers within emails to do similar.)
Update: I am listening to the feedback presented here, though please know there is a whole team of people working on this feature, trying to bring needed email protection to our mainstream user base. Email protection as a concept is hard for people to understand and the team felt that this in-context onboarding was the best way to explain it. However, we will now revisit this given the feedback.