I noticed that the English and German Wikipedia logos look slightly different at 1x resolution (apart from the obviously different tagline, which is translated):
If you open both images (or enwiki.png and dewiki.png on /static/) in new tabs and quickly toggle between them, you can see that the “Wikipedia” letters are arranged sligthly differently, and all the lines in the puzzleball seem a bit heavier in the English version.
At 2x resolution, the puzzleball and Wikipedia wordmark look identical:
enwiki-2x.png, dewiki-2x.png
And when I open the 1x versions, zoomed to 200%, next to the 2x versions, it seems to me that dewiki.png is closer to dewiki-2x.png than enwiki.png is to enwiki-2x.png:
So I think it’s the enwiki.png that is slightly wrong, and should perhaps be updated. You can also compare the static enwiki.png with the Commons thumbnail at the same resolution – the latter has the same puzzleball and wordmark as static dewiki.png:
