The keys and values in the $qa_content array vary depending on the configuration of you site. However, the closest thing to what you're asking would be the output of function qa_content_prepare.
Also there are a few comments on some keys of the array in the documentation here.
Important note: That array can be modified by any theme or plugin so you should never trust a given key or value exists or it is of the type you're expecting it to be.
