The linked article is rather sensationalized, the summary even more so

Here's the actual text. It's from Microsoft's own SEC filings, in the "Contingencies" section of the notes, not from the EU - this is Microsoft's opinion of what the European Commission might require, not something from the Comission itsself.

While computer users and OEMs are already free to run any Web browsing software on Windows, the Commission is considering ordering Microsoft and OEMs to obligate users to choose a particular browser when setting up a new PC. Such a remedy might include a requirement that OEMs distribute multiple browsers on new Windows-based PCs. We may also be required to disable certain unspecified Internet Explorer software code if a user chooses a competing browser.

Note, in particular, no mention of specific other browsers.