50ms → 50 ms: I always write 50ms but NIST agrees with you so you are probably right 
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Since the items are not complete sentences, I would not have added periods after the bullets in https://wiki.developer.mozilla.org/en-US/docs/Web/API/Long_Tasks_API%24compare?from=1556396&to=1592775 . See also this thread. But that’s just my opinion really, and I don’t feel too strongly.