A single quote is actually shorthand for the quote special form
'foo
(quote foo)
'(1 2 3)
(quote (1 2 3))
It basically does not evaluate its arguments but returns whatever it is. So instead of the value of foo, it the symbol foo. The list example does not evaluate it either, it would normally try to apply the first element as a function, but instead we get the list of numbers.
While I don't write Scheme, I believe it is Scheme -- one of the goals of the GNU project is to have every GNU tool be configurable with Scheme (which is why GNU has a Scheme implementation as opposed to a Common LISP implementation).
Loop unrolling as shown by the author is quite common in maths functions. It is still quite readable and ensure good performance. Openblas use a similar tricks in the old days when there is no intrinsics. Not sure for now.
GCC is still in the NDK today because some of gnustl's C++11 features were written such that they do not work with Clang (threading and atomics, mostly). Now that libc++ is the best choice of STL, this is no longer blocking, so GCC can be removed.
Handset vendors and, especially, mobile network providers, would rather ship their handsets with proprietary unmodifiable software that they can cram with antifeatures that will be that much harder to detect or remove.
Having said that, the reports I've seen contain scant actual evidence that Google actually plan for Andromeda to replace Android, or even that Andromeda is at all important to Google. I take these reports with a mountain of salt. I remember that the "Pixel 3" was definitely just about to be announced back in late 2016, and was definitely going to be running Andromeda OS.
The OS Fuchsia, including the kernel Magenta, appears to be open source, mostly under BSD 3-clause, with parts of the kernel under MIT and similar licenses.
Open sourcing the product will help the competition to catch up quickly, all they have to do is take googles product and change its look. The next half is infrastructure, which companies like Microsoft, facebook, amazon, alibaba all have. Plus services like AWS will help future version of dropbox & netflix.
A good example of that is Visual code. I am sure some at github (atom's paprent) is pissed.
There's a ton of good reasons to replace Android beyond licensing. Security being the largest one. Fuchsia is designed with security in mind from the ground up, Android arguably is not (at least not from the sense of what is considered security today).
