Why reply-to isn't available in webclient and striped from bridge sent email ? (what is the security no-go decision ?)

I use a mailing list like email :
collective@collective.org with redirection to :

• internal-archive@collective.org
• my personal proton email
• the personal email of each other collective member.

When I reply from my personal proton email to a collective@collective.org sent email, I can't set a reply-to field to help the one I'm talking to reply to collective@collective.org.

If it was a feature request, I would ask you to add it, but as a question :
Now, you know my use case, i'm not the first to ask (from 2015 for the first comment to now). My question is : what the security issue to implement this ?

• is it spam or trust related ?
• is it technical limitation linked to e2e PGP encryption ?
• is it something else ?

The payload names no source file, test, or entry point. Start with the webclient use case and the issue's questions about spam, trust, and end-to-end encryption; done should be a documented decision on whether Reply-To can be supported and the security rationale.