Installing and configuring the package basically enables the usage of the new index based search. In the first iteration only the mail module will be supported. By default the feature is disabled, even if the package is installed. That is because it has a high impact on the whole OX environment.

The new package consists of the following OSGi bundles:
com.openexchange.index.solr
com.openexchange.mail.smal
com.openexchange.mail.smal.impl
com.openexchange.service.indexing
com.openexchange.service.indexing.impl
com.openexchange.solr

It also contains some command line tools contained in normal Java projects:
com.openexchange.admin.solr
com.openexchange.admin.index