nltk_data/grammars/large_grammars.xml

<package id="large_grammars" 
         name="Large context-free and feature-based grammars for parser comparison"
	 webpage="http://www.informatics.sussex.ac.uk/research/groups/nlp/carroll/elsps.html"
         contact="John A. Carroll"
	 license="See the individual grammar files"
         languages="English"
         unzip="1"
         />