I noticed that my windshield has very minute scratches in it as well. Longitudal in nature. More noticable in bright sunlight. They look somewhat evenly distributed making me think this is the glass itself. Perhaps this is a special glass used for the heads-up display?

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2013 BMW X6M-current
2013 Audi S4-current
2007 BMW X5 4.8i (E70)-sold