This file is for storing content reference text -- short pieces of text for reuse in multiple documents.
<table conref="conrefs.dita#conrefs/element_ID"/>
<table conref="sourcefilename.dita#sourcefileID/element_ID"/>Note that if you want something to validate, you'll have to include any required tags in the dummy text that gets replaced. A table is a good example...it requires a bunch of internal tags, so it's not as easy to conref it.