the confusion comes from the cleverness of the design of UTF-8, by making the first 128 bytes have the identical encoding to ASCII most software
just works when it encounters UTF-8 data, so long as all they encounter are those characters.
The facts are that UTF-8 is a variable length encoding, and can encode any Unicode character. UTF-8 is the encoding of choice in modern software as there are no byte-order issues and it is extremely compact for western characters.
Many legacy systems have given their own names to their level of Unicode support, but that does not change the standards. Some major systems pretend to support it and still do not do it properly.
It appears that AKG does nothing special, consuming rendering UTF-8 data as it if was ASCII
There are software libraries such as ICU which are freely available and used by all major operating systems under the covers to provide correct Unicode support, including reliable conversion from UTF encodings to other code pages and encodings as well as different collations (sort order) for different cultures and upper and lower casing rules which vary by culture, support for right -to left scripts, etc.