But say I give it a new piece of text it has never seen before. Can it answer questions about that or it won’t really care about what’s in that text?

It will give an answer, whatever is formed by extending the input you give it. The answer will be based on the text you provide, so in that sense it "cares" about it. Whether the answer is any good is another matter. But maybe it will find something based on its training data that relates.