Some of the top browser makers around have issued a letter to the European Commission (EC) alleging that Microsoft gives the Edge browser an unfair advantage and should be subject to EU tech rules.

A letter seen by Reuters, sent by Vivaldi, Waterfox, and Wavebox, and supported by a group of web developers, also supports Opera’s move to take the EC to court over its decision to exclude Microsoft Edge from being subject to the Digital Markets Act (DMA).

As Edge comes pre-installed by default on Windows machines, users must navigate the Microsoft offering in order to download their browser of choice. The letter states that, “No platform independent browser can aspire to match Edge’s unparalleled distribution advantage on Windows. Edge is, moreover, the most important gateway for consumers to download an independent browser on Windows PCs.”