This appears to be a report from their mail server and is because of the rua field that you received it. By setting it to reject, you're telling them to not accept any email from someone that is spoofing your domain. I think the only other field you'd want to set is pct as it specifies what percentage of email this rule should apply.
Stand left, walk right on escalators and moving walkways
This may be region-specific. In my area, I generally see it the other way around. But unless you're the only person, it's usually pretty clear which side to stand.
When I was a kid, I passed a marble. It was quite painful when exiting the stomach, but I'll never forget the sound of it hitting the porcelain afterwards.
I think for issues like this it may be good to develop a practice of using the spoiler tag with a warning attached. This way it's up to the reader to decide if they want to read it and is flexible enough to cover all of the various use cases.
I have been working on a Wayland Tiling WM and have thought about expanding more into the DE space. While it's finally starting to get to a good spot, it's pretty daunting to consider all of the other items that need to be developed for a fully-featured DE. Especially when it's something I'm doing as a side project after my day job. I think for anything bigger it'd require financial backing, for which open source projects are still struggling to find a good solution.
Pig ears and antlers have always worked well for me. You can buy sizable bags of them for pretty cheap, so it's not a big deal if they burn through them quickly.
What might be interesting would be to have it displayed, but grouped by instance. That way we could see some data and potentially uncover troll instances or attempts to brigade the conversation without opening ourselves up to personal attacks.
This appears to be a report from their mail server and is because of the
ruafield that you received it. By setting it toreject, you're telling them to not accept any email from someone that is spoofing your domain. I think the only other field you'd want to set ispctas it specifies what percentage of email this rule should apply.