The log level here is only for debugging xDebug itself, not for debugging PHP.
adding the single line to the php.ini.hbs file does work.
{{#if xdebugEnabled}}
xdebug.mode=debug,develop
xdebug.log_level=0
{{else}}
xdebug.mode=off
{{/if}}
xdebug.client_port=9003
xdebug.start_with_request=yes
xdebug.discover_client_host=yes
It would be a nice addition and pretty simple to do.