I've tried searching of this, but the results I get are either related to the show or point to Fandom profiles of Kate Kane that are just too broad and lack any mention of this revelation.
I know Kate Kane was introduced during the 52 weekly comic series/event. And I know her history was potential rewritten in New 52.
I just want to know the details of how Kate learn Batman was her cousin. For both Post-Crisis Kate Kane (Pre-New52) or New 52 Kate Kane, I would like to know how she discovered or who told her. Ideally, if you could include the issue or comic, I'd appreciate it.