In VCF files, what character encodings are used in practice?

What character encodings are *expected *for the format?

The examples I've seen seem to include single-byte characters. It's not clear whether it's intended to be 7-bit US-ASCII or 8-bit Latin1.

The [4.2 format specification][1] doesn't mention encodings for VCF files. (It does specify that Unicode characters are not supported in characters and strings in *BCF *files)

 [1]: http://samtools.github.io/hts-specs/VCFv4.2.pdf
https://github.com/samtools/hts-specs/blob/VCFv4.3/VCFv4.3.tex

> The character encoding of VCF files is UTF-8.  UTF-8 is a multi-byte  character encoding that is a strict superset of 7-bit ASCII and has the property that none of the bytes in any multi-byte characters are 7-bit ASCII bytes. As a result, most software that processes VCF files does not have to be aware of the possible presence of multi-byte UTF-8 characters.