Authorization Basic

https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Authorization

<credentials>

If the "Basic" authentication scheme is used, the credentials are constructed like this:

• The username and the password are combined with a colon (aladdin:opensesame).
• The resulting string is base64 encoded (YWxhZGRpbjpvcGVuc2VzYW1l).