GoLang Source Code is DEFINED as UTF 8

Quotation from Golang.org: (https://blog.golang.org/strings)

Source code in Go is defined to be UTF-8 text; no other representation is allowed. That implies that when, in the source code, we write the text ⌘ the text editor used to create the program places the UTF-8 encoding of the symbol ⌘ into the source text. When we print out the hexadecimal bytes, we're just dumping the data the editor placed in the file.

In short, Go source code is UTF-8, so the source code for the string literal is UTF-8 text. If that string literal contains no escape sequences, which a raw string cannot, the constructed string will hold exactly the source text between the quotes. Thus by definition and by construction the raw string will always contain a valid UTF-8 representation of its contents. Similarly, unless it contains UTF-8-breaking escapes like those from the previous section, a regular string literal will also always contain valid UTF-8.

Some people think Go strings are always UTF-8, but they are not: only string literals are UTF-8. As we showed in the previous section, string values can contain arbitrary bytes; as we showed in this one, string literals always contain UTF-8 text as long as they have no byte-level escapes.

To summarize, strings can contain arbitrary bytes, but when constructed from string literals, those bytes are (almost always) UTF-8.