Where is the source extension_additional.conf file

I have modified the extension_additional.conf file to include a “Callback” feature when stations are busy.
I’m replacing the BUSY script with my own code in the “vm_msg” macro.

HOWEVER, is seems that anytime a phone is added, modified, or deleted, this file is rewriten and my changes are lost.

I’m hoping there is a source file somewhere in the trixbox that is used when rewriting the extension_additional.conf file.
If I can rewrite that file, my changes wont be lost.

If this is correct, what and where is that filed located?

TIA,

Ira

This file is not part of Asterisk, so it is probably part of the GUI you are using. It should not be unexpected that the GUI creates it from its own internal data structures.