Defrag Windows?

That’s adorable.

Also, is it not a window in the door? 🤔

You can get vinyl adhesive-backed sheets to get this look (and many others!). You just cut and stick them.

If you go that route, apply to the glass fully, then use a razor blade to cut around the edges, else you’ll likely end up with skew or edges that don’t meet the corners. (Learned that trick from a vinyl graphics installer)