Apple is opening up its powerful App Store for the first time ever. It's not happy about it.

• Apple spent years resisting efforts to open up its App Store and other parts of its iOS ecosystem.
• Now it's happening — in Europe — because of a new law from EU regulators.
• It's a major concession from Apple, which made it clear it's not happy about the change.

For years, Apple has been insistent that it needs control over its App Store and other key parts of its iPhone ecosystem, even in the face of increasing complaints from regulators.

But now, for the first time, it is going to grudgingly open up many of those elements — because of regulatory pressure.