The explanation starts with unicode ; an industry standard which creates the specification for thousands of different symbols and characters.
Use for sad ironic purposes only. This doesn't mean there's an error with this translator, it just means the website's font doesn't support that character. The only exception is if your paste destination has a font which doesn't support some unicode characters.
Fraktur saw a brief resurgence after the war, but quickly disappeared in a Germany keen on modernising its appearance. First used to decorate religious texts, including the earliest printed book:the Gutenberg Bible.
Mildly off topic, but you might also be interested in Facebook emojis - that's a massive searchable list of all the emojis that you can use in your Facebook posts and chat.
In that case, you'll see a generic "box" in which was created when the browser tries to create a fancy letter.