Sieve reject with ORIG-TO vs TO

Hi,

The bounce message generated by the reject extension has what looks like a hard coded message prefix that comes before the configurable reason text:

"Your message to <username> was automatically rejected:"

In some cases, the <username> is NOT the original-to address, which can cause confusion to the sender or expose private aliasing data that some people might want to hide.

Is there a way to make the reject extension use the original-to address in that hard-coded message prefix?

Is there a way to completely customize the FULL message?

Is there a way to customize the headers for such messages?