In the Advanced settings, Triggers -> Failure - Any listed "Developers" but not "Recipient List." When I add Recipient List my console output says:

Checking if email needs to be generated
Email was triggered for: Failure - Any
Sending email for trigger: Failure - Any
messageContentType = text/plain; charset=UTF-8
Adding recipients from project recipient list
Adding recipients from trigger recipient list
Setting In-Reply-To since last build was not successful
Successfully created MimeMessage
Sending email to: <me>

If not including the recipient list is the default, that's not very helpful. I would not have expected to have to open Advanced settings to get basic functionality.

A separate issue, I'm sure, but $BUILD_URL doesn't seem to include a protocol. The only reason I am using this plugin instead of the built-in functionality is so that my notification has a clickable link to the job. I guess I at least gain the ability to put "http://$BUILD_URL" in the body but it's odd that the URL is incomplete.

Not including the recipient list by default for failures is a historical issue. It was that way for a long time and when I tried enabling recipient list for Failures, people were upset that the behavior changed.

For BUILD_URL, it takes it from the following: jenkins.getRootUrl() + build.getUrl(), check your URL setting in the Manage Jenkins area under "Jenkins Location Configuration"

Maybe the distribution needs to not be an Advanced feature.

Sadly, when I tried that, people didn't like it either. I can't please everyone.

Can you verify that "Recipient List" is setup in the Failure trigger in the Advanced area in the job itself?

 
How do you do this with a pure pipeline job?

e.g. using the github organization folder where you cannot edit individual jobs because they are generated from repos/branches in GitHub.

You don't, pipeline usage doesn't use failure trigger. You just add the recipients directly in the pipeline call to email-ext.

slide_o_mix

But I get no recipients (unless I trigger the build, in which case I get myself as a RequestorRecipient) for culprits, developers, etc.

Please don't hijack this issue. If you have questions, use the mailing list.

I suppose you should use "to:"/"cc:"/"bcc:" extensions in the mailing list before recipient's address.