Me 262 A-1a/u3 stencil

[JonCOlsen]

I've noticed that on most (if not virtually all) Me 262 A-1a/u3 reconnaissance versions, there is dark rectangular-shaped stencil consisting of four smaller rectangles. It always appears on the port side of the aircraft just below the ventilation scoop under the windscreen.

In this photo, you can see the stencil quite clearly. It intrigues me that this stencil can be seen only on reconnaissance airframes.

Any thoughts, theories, or knowledge about this stencil? I'd love to know the exact significance of it, if possible.

Thanks!

Regards,

Jon