In the module Phrasify, breaks between phrases are determined. Phrasing is handled by Phrasify_German (file ims_german_phrasify.scm) if the parameter 'Phrasify_Method is set to 'Phrasify_German.
Phrasify_German first checks if there are pre-specified tones on any of the words in the utterance (i.e. if any of the words has a feature 'tone' specifying a boundary tone). In this case, we assume that we want to assign breaks exclusively where they have been specified. Therefore, phrase_cart_tree (which will later be used for prediction of breaks, as 'Phrase_Method is 'cart_tree for all German voices presently defined) is reset to german_phrase_cart_tree_from_tobi.
Otherwise, the default german_phrase_cart_tree as defined in ims_german_phrasify will be used to predict phrasing, unless it is reset (in ims_german_voices) to some more elaborate tree.