Google Apps for Domains used to have a catch-all feature. Now the docs [say](https://support.google.com/a/answer/33962?hl=en):

>If you’re using another G Suite edition, the Email routing setting with the Route to catch-all address control is no longer supported. Instead, you use the Routing setting to configure catch-all addresses and routing.

but they don't actually have any instructions on how to do it.

Specifically I want to replicate the old behavior which is that if someone sends a message to `[email protected]` it gets forwarded to `[email protected]` in such a way that `[email protected]` can setup accounts in Gmail and can reply to the messages as `[email protected]`.

If I check my legacy Google Apps for Your Domain emails and check the headers of a message sent to `[email protected]` I see absolutely nothing in the header that suggests it was forwarded to `[email protected]` and yet the mails show up in the inbox for `[email protected]`. This is important because when I reply, if I've added the `[email protected]` to my accounts under Settings>Accounts->Send Mail As... then I'm able to reply as `[email protected]` and not as `[email protected]`. For this to continue to work I assume the mail still has to be marked as `to: [email protected]` and not `to: [email protected]`.