Why does the B-2 Spirit have a pattern of thin white lines?
@RAC and @Hobbes are right. I found a high res photo on defense.gov.

The crop below shows WALKWAY and NO STEP instructions indeed. Similar to what you'd find on a jetliner's wing.



It makes me wonder though why the person below did not abide.


Source: https://tucson.com/news/national/costly-b--bombers-both-tech-marvels-hangar-queens/article_273b0f50-71f6-56ca-a399-401e342658c1.html