In the rich text editor:
@CainbutnotAbel
In a comment:
[CainbutnotAbel](https://chowlings.com/user/CainbutnotAbel)
For Names and Avatars:
In the rich text editor:
%CainbutnotAbel
In a comment:
[![CainbutnotAbel's Avatar](https://chowlings.com/images/avatars/default.jpg)](https://chowlings.com/user/CainbutnotAbel) [CainbutnotAbel](https://chowlings.com/user/CainbutnotAbel)