Naven
Glossary
Message editing
Changing a message after it has been sent.
The argument for it is typos; the argument against is that an edited message can change the meaning of a reply below it. Most platforms compromise by marking the message as edited, which preserves the reader's ability to notice.
A time limit is the other common guard.
Where Naven stands
Naven marks an edited message as edited, and an edit is screened before it replaces the original — otherwise the screen could be bypassed by sending something harmless and editing it afterwards.