Those might be functions that alter context of the closure rather than being returned. Or it might be some Swift compiler magic?

So far I found out it's implemented via parameter attribute [1]

[1]: https://developer.apple.com/documentation/swiftui/viewbuilde...

More details in the proposal [1]:

> the basic idea is that we take the "ignored" expression results of a block of statements — including in nested positions like the bodies of if and switch statements — and build them into a single result value that becomes the return value of the current function.

[1]: https://forums.swift.org/t/pitch-function-builders/25167

Ouch, that’s pretty awful…

They look like initializers. Functions are lower-case by convention in Swift.

That is convention, but there’s no need to follow it ;)