Is it an invasion of privacy to ask a lecturer for details on their LaTeX editor setup? I (very) recently completed a Real Analysis course at my university. One day during the course I went to see my lecturer regarding an error I spotted in his notes. 

The notes set for our course were written and typed up by our lecturer. Upon verifying this error my lecturer opened up the source .tex files for his notes and corrected the error and recompiled the notes in front of me (he was sitting down at his desk and I was standing next to him).

As someone who's used to typing up stuff in TexStudio I was very intrigued by what LaTeX editor he was using as it seemed like something I never saw before, and honestly it seemed like the ideal LaTeX editor setup at first glance. I thought of asking him at the time but I assumed that I would be crossing some boundary.

Fast forward to now, and I have quite a good relationship with this (now former) lecturer of mine, having completed his course just a few weeks ago. 

Would it be frowned upon if I sent him an email asking him what his LaTeX editor setup is? (I'm assuming it's Emacs with auctex and with some sort of custom theme). Would any lecturer consider this as an invasion of privacy or crossing some boundary?
I don't think anybody would look on such a request as an "invasion of privacy"; if anything, most people are happy to share the names of tools they use. I wouldn't worry about it, but don't be alarmed if you don't get a response, either, since this would be a "low-priority" email for most people to respond to (unless it's someone they're actively supervising or collaborating with!).