Newest iPhone 7 claims to have "Wide color display (P3)". What exactly is this, a color space? Could this be Adobe RGB, or just a different space created by apple?
How does it compare to sRBG and Adobe RBG?
Ok I've found it. It's DCI-P3 standard:
Most modern android smartphones are already able to display the circle inside the red square, but probably are converting Adobe RGB or DCI-P3 color space to sRBG instead of displaying correctly the original one.
Your answer is a good approximation, but there's one detail I'm mentioning here for completeness:
Apple devices use a color space called Display P3, which is very similar to DCI-P3, but uses a different gamma of 2.2 rather than the 2.6 that DCI-P3 uses. Software that processes photos or videos needs to account for this difference; otherwise colors will come out wrong.
However, Display P3 has the same gamut as DCI-P3, so at a high level, you can think of them as the same thing.