I can't for the life of me find the questionmark. If it might be useful, I'm using marshmallow on an sm-G920F (Galaxy S6). Default settings, except for having changed portrait mode to 5-row compact layout. I like it in portrait for using it in vi for example (swiftly being able to use esc). I can't imagine it being meant to be MIA, so I thought I'd send a bugreport.
Edit: The / is ofcourse also nowhere to be found
Well, / is in the lower right-hand corner, right above →. ? is Shift/.
Tip: Turn on Settings > Theme and Label Settings » Labeled Alternate Keys: Show all hint labels to see alternate keys more easily.

I see now, it was hidden under the speach to text button, thanks!
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I see now, it was hidden under the speach to text button, thanks!