Android is more complex. The base platform is open source, and anyone can download the AOSP code, compile it, and make a phone or tablet. Google wouldn’t even know that you’d done it. But the value is increasingly in the services layer, and this in turn has become conditional on what Google dictates.
If you want fast accurate location data, your device needs Google Play Services. If you want the best app store, that’s Google’s. Some apps will just refuse to run. They’re all part of the proprietary binary package that comes from Google, called Google Mobile Services (GMS). The conditions for meeting this are nominally administered by a third party. Such conditions are specified in the contract called a Mobile Application Distribution Agreement.
"Android GMS is a big binary blob that you must integrate. Google has ratcheted it up over the past year. When you sign a MADA, you know it will change,” one OEM
told us.
There were further complications to this antitrust investigation: nobody wanted to talk. The European Commission had to
threaten phone makers with fines if they didn’t submit answers to the EU's questions, specifically about the MADAs.