xmlrpc_errors INI setting

Hey, while working on cleanups for the internal error handling code, specifically extracting different rendering logic into pluggable hooks ( https://github.com/php/php-src/pull/5484) I came across the ini settings "xmlrpc_errors" and "xmlrpc_error_number", prominently integrated and used in main/main.c Both are used to allow users to change the display rendering of errors while display_errors=1 and these settings were added in 2001 and nothing changed much about this since then. I am wondering if this code is not better moved to ext/xmlrpc extension instead of being in main/main.c - this would be similar to how ext/soap handles errors in the extension already. Downsides: - People can currently use this setting when doing their own xmlrpc, however that anyone uses this setting looks so unlikely, because its global - With the potential unbundling of ext/xmlrpc this could also mean the ini settings get moved out of core entirely. Do you think this small BC break moving the settings to ext/xmlrpc is acceptable as part of decoupling error displaying from php_error_cb and main.c? Has anyone seen this been used in a project?