The legal question is whether the exclusivity terms in the licensing deals are anti-competitive given Google's dominant market share in Europe.

"handset-makers that wish to pre-install Google Play must, among other apps, also add Google Search and make it the device’s default search service; if they want to share in Google’s ad revenues they have to exclusively pre-install Google Search; and if they pre-install Google’s apps on any of their models, they must commit to install only Google’s standard version of Android on each and every one of their models."

In tightly controlled ecosystems the default state is effectively what most consumers will keep and use. This is sometimes informally called the power of default. Entire billion dollar markets can rise and fall based on something as simple as an opt-out versus opt-in policy. It's a little like that Supreme Court ruling that said ''the power to tax is the power to destroy''. The power of default is not much different especially when you control the entire underlying OS. Anti-trust regulators are right to focus on what these default settings are.