I think you want to lift the front wheel off the floor, by the frame not by the wheel or forks or handlebars, and then jiggle the front end to see if there's play ... i.e. when you pull the front wheel toward the front of the bike, is there play? Can you jiggle it, or is there no slop while still allowing the steering wheel to turn left and right freely.
Warning: I don't know jack. I just post online when I'm bored and think I might have a hunch about something
Edit: Seems I was pretty close:
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