I was wondering why you can use "Extended Latin A" Symbols and not others. why not adding more ? ( even adding japanese/korean etc. . )

炭素含有量が 1.2 % 以 들어가는 자유 백과 你好 giản là một đoạn văn bản giả, được dùng vào

Above are samples of Japanese, Korean, Chinese, and Vietnamese from the web. They're showing here, so I'm not sure where or why they aren't working for you.

Edit: I'm blind, disregard.

[quote=Quivico]They're showing here, so I'm not sure where or why they aren't working for you.[/quote] Given the title of the thread, I'd assume the "where" is in the username.

I assume one of the reasons is because of URL handling: Each user has a profile with the URL of their username: https://www.speedrun.com/user/Oreo321 Handling URLs with special (non-ASCII) characters isn't really an easy task; and they might not work for different users the same way, based on localization, browser, encoding and some other stuff.