Upcomming featue in 1.12 introeudced advance fultext format, this in turn needs a way for API consumer to know abut this, this in turn relies on a new interfaxce for search engines.

So in order to make sure new versions of Solr Bundle one it implemented this still works on eZ Platform 1.7LTS, we need to back port this interface, even if it won't be exposed in API before in 1.12 and higher.