In T15719#15304, @Tgr wrote:

Given how it's displayed on the Gmail UI, IMO unsubscribing from all emails or at least all emails of the given type (e.g. all Maniphest emails if it's a Maniphest notification) is the only thing that makes sense. If I mark an email as spam, and then use the unsubscribe option instead, I would not expect to continue getting identical email from all the other tasks.
No idea how (or if) other email clients handle the header, though.

In T15719#15280, @avivey wrote:

I'm left wondering when a "list-unsubscribe" header is appropriate - looks like anything that would need it will also need the one-click?

In T15719#15280, @avivey wrote:

This suggests to me that there isn't a third category - everything is either promotional or transactional.

I'd argue that none of our emails are "marketing" or "promotional" (or "commercial"), even if it's hard to claim they are "transactional".
But as long as 98%[1] of the users agree that our mails aren't commercial, we don't need the one-click solution.

Do all messages require one-click unsubscribe?
No. One-click unsubscribe is required only for marketing and promotional messages. Transactional messages are excluded from this requirement. ...

In T15719#15272, @avivey wrote:

1. Would adding List-Unsubscribe: https://we.phorge.it/settings/panel/emailpreferences/ header be enough to solve this?

In T15719#15276, @Dzahn wrote:

@phab1004:/srv/phab/phabricator/bin# ./mail volume

Killed

In T15719#15272, @avivey wrote:

using bin/mail volume, to see if they need to worry about this. It just collects all mails created in the last N days and counts them by user.

This is promising, from the Email sender guidelines FAQ:

Re: 1), the doc makes it sound like not, but I'm not entirely sure.

1. Would adding List-Unsubscribe: https://we.phorge.it/settings/panel/emailpreferences/ header be enough to solve this?

What issues did you run into when using ./bin/mail send-test?

Sorry for the confusion. I mean that the /mail/ page is the Mail Dashboard that allows to see both Inbox and Outbox (visible from the left sidebar menu). For example this is the exact Outbox sub-page:

Once I get back to working with that instance, I suppose I'll go to my inbox -- where (you seem to be implying) it will show me errors from when the system sent me the initial authentication email? That seems like an odd location, but ok.

Indeed :)

That sends me to my inbox here -- do you mean, on my own instance?

Nice trick for you: to register a new identity try adding +something after your email username. Example: smith+test1@example.com. That is a secret feature of mailboxes.

Have you already seen this page? maybe useful?

Also, the authorization process is rate-limited to 3 emails per hour, preventing me from using that to send an additional test email that way

"Do nothing" does nothing. It's mostly for working with the "Other Herald Rule" conditions.

Do you remember what the "Do nothing" Herald rule is about?

I think you can get there using herald: