[Anthony-G]

One of the reasons I like mutt is that I can easily edit the “From:” header (I have Postfix configured with multiple email aliases for my primary email account).

In my experience, most mail user agents allow editing the Subject header. Even Outlook Web Application that I have to use in work allows me to change the Subject line when a conversation thread has veered off-topic, e.g., “Server replacement [was: Windows 11 upgrades of client PCs in Accounts]“

[euroderf]

Oh but I don't mean edit the Subject in new replies. I mean edit it in an email already/currently in the Inbox.

[Anthony-G]

Ah, OK. That’s very cool. I hadn’t realise that was possible. I might have to borrow that technique. Thanks!