Unfortunately the base64.asp file is zipped up in  `bundles/iis_ad_asp_jwt.zip` so none of the Base64 encoding actually takes place in the `classic_asp_jwt_with_ad.asp` file, nor is it immediately visible in this diff. 

The `Encode_UTF8` function iterates over the characters in a Classic ASP string (in this case, a person's name from a directory), looks up the Unicode code point for each character, and adds an encoded version of that code point to an output string. The output string is never represented to the end-user, but instead passed to several functions, including the base64 encoding function. The whole process only seems to work because of the way Classic ASP represents strings in memory.

`Encode_UTF8` is taken from the 'sample' Zendesk Remote Auth script that we used to provide in-product -  it's not something I wrote. I can try to find a more robust, explicit way to convert a Classic ASP string into a representation of Unicode code points but it seems like the language doesn't handle Unicode particularly well.