Did you really have the nerve to ask me Who and How For?
Ok, here is your answer(s).
None. uh. ya. business.
No really. How indeed! How is it even remotely tangential to your oeuvre to know WHO and HOW FOR?
And what is 'how for?' even asking? I understand 'why come?' as an almost type of question, but your u-turn of a phrase 'how for?' gets my semiotics engine baffling. We'll have to come back to the latter half of your query later.
So instead let's push your 'Who' question of a premise a little further down the road. What if 'Who' is a someone you know? Does that create a mandate for snooping, simply because you are aware of their existence? OR, because of your mutual other awareness, do you now both share a bond in an expectation of privacy? It is almost exclusively a human quality, our fundamental choice whether or not we reveal any part of ourselves to one another, or many others.
With me so far?
Well too bad. Because now we have to ask; What if 'Who' is NOT someone that you know? Is their expectation of privacy with you, the unknown individual, diminished by a lack of personal familiarity? No, it is not. I posit that one's expectation of privacy from those they don't know is much stronger than with people they know.
Why does your paltry 'want to know' complex tend to eclipse any sense of or respect for, a basic human decency? Could it be caused by modern society's over heightened appraisal of TMI in this modern age? Is it a matter of your own proprietary security? Or maybe it's just your big nose? Your big nose not belonging wherever you goes and sticks it?
You'll have to answer those last few Bon Mots on your own time...
Now it is time for your answer(s).
The answer to Who is...
And the answer to 'how for?'
That's how for.