This is a bit unrealistic... asking someone what spacer.gif was used for could in theory work the way you describe, because it was something wide-spread and doesn't require you to recall too much details, just a general idea. On the other hand, issues like this xml mime-type thing are just too specific to recall after all that time. Frankly I don't remember half of the things that I've read last week and this was decades ago...

On the other hand, asking theback-end programmer what is a shebang line is totally legit in my opinion, nothing BS about it.