Does any one know what that open panel in front of the windshield is for?
All I can offer is a potential possibility, depending on year.
Have seen as far back as late 1980s this photo of a M&StL EMD FT described somewhere as modified with this hatch in top of nose to meet a government requirement calling for easy access to windshield to keep it clean.
I wish I still had Kalmbach's early 1980s reply to the letter I wrote about this photo in their Diesel Locomotive Cyclopedia mentioning it and asking what it was about & was it indeed made from a F unit side window as it appeared to be.
Their reply to my question about the picture of this hatch in their book was that nobody ever did hatches like that.

I trashed their letter because it was so in-your-face absurdly, ignorantly, wrong.
Should have kept it as a sellable souvenier!