Cool, although I feel if on one side you have Java, JavaScript, Python, Go and on the other Perl, PHP, C/C++, Ruby, Rust it's hard to say overwhelming majority in either direction.

Also someone below claims python byte arrays can be considered mutable strings, although I have no idea of the stringy ergonomics of that and whether it would be convenient to do - I try to avoid python too.

... and honestly, since java has both stringbuffer and string I feel it's really in the "has mutable" camp too