There’s a lot going on in the browser world these days, and after Microsoft announced it’s moving to Chromium for its very own Microsoft Edge, Mozilla is also making silent changes that do not sit well with its users.

The latest version of the browser has started displaying ads in new tab pages, with early reports confirming this happens on all supported desktop platforms.

As reported by users on reddit (via TechDows), a small popup that shows up at the bottom of the screen includes a link to Booking.com.

“Ready to schedule that next family reunion? Here’s a thank you from Firefox. Book your next hotel stay on Booking.com today and get a free $20 Amazon gift card. Happy Holidays from Firefox! (Restriction apply.)” the message reads.

Clicking the “Find a Hotel” button takes users to Booking.com.

You can disable the feature from settings

At this point, it looks like these messages only show up occasionally and only for a specific set of users, so there’s also a chance that Mozilla is also conducting a limited experiment. We haven’t been able to reproduce this behavior on old and new installations of Firefox 64.

Officially, Mozilla calls these adds “snippets” and the company allows users to disable them from the settings screen of the browser. You can head over to Preferences > Home > Snippets to turn them off.

Mozilla hasn’t released a statement on whether the company is just running an experiment or this is expected behavior in Firefox 64.

Nevertheless, it goes without saying that users aren’t happy with ads showing up in the browser, and although they are allowed to disable the feature, the simple fact that it comes enabled may cause more frustration in the existing user community.

More official information from Mozilla engineers should be provided in the coming days after the holidays.