Originally asked by Riddhi on 26 October 2020 (original question)
Answer by Francis Martens (Exalate) on 27 October 2020
A mention in a comment is noted down as something like
[~john.doe]
When the other side receives that message (containing the tag in the body), Jira will try convert it to a mention. This will only work if you have a user ‘john.doe’ in the user directory.
In case that john has another userkey in the directory (such as johnd or jdoe), then you can map the incoming mention to the appropriate user.
As an example - we once wrote following Atlassian article
How to sanitize mentions when synchronizing issues