Swift `String.Encoding`: `.unicode` vs `.utf16`

Question

String.Encoding struct features several unicode related implementations:

https://developer.apple.com/documentation/swift/string/encoding

• utf8
• utf16 and its modifications
• utf32 and its modifications
• and suddenly, unicode

What is this unicode case, what's it for? Is this just an alias to some particular encoding like utf16? Or maybe, this is just some umbrella value which means "any unicode encoding" and in some contexts it will evaluate to utf8, and in some - to utf16?

Answer 1

Looking at the source code for swift-corelibs-foundation, utf16 is the same as unicode:

public static let utf16 = Encoding.unicode

This makes sense, as the NSStringEncoding (which presumably is what the cases of String.Encoding are based on) values are also like this. The docs for NSUTF16StringEncoding says it is an alias of NSUnicodeStringEncoding.