In the following Washington Post's article (Feb. 13) reporting the outcome of CPAC 2011, I found the phrase if you must know.
I think this phrase means though it may not be essential knowledge that you are supposed to have, or just for your reference. What is the difference of nuance among if you must know, you may know, and you might know, which is difficult for non-native English learner to discern?
The three-day Conservative Political Action Conference ended Saturday afternoon with a meaningless presidential straw poll (if you must know, libertarian gadfly Ron Paul won for the second year in a row).