That must be a feature of ebay.de -- I have not noticed similar notifications on other eBay sites. Perhaps it appeared once on ebay.com but if so, it went away after being dismissed, as it should.
It does not appear on all ebay.de pages, though. Just the main ebay.de page when using a mobile browser in mobile or classic mode. If you switch to desktop mode, the notice does not appear.
Actually, I just now noticed a similar message at the top of ebay.fr in white, but the message went away after being dismissed, and so far has not come back, unlike the German counterpart which apparently cannot be permanently dismissed.
You may want to post about this on the German eBay community discussion boards:
https://community.ebay.de/t5/Diskussion/ct-p/13
Perhaps someone there has a workaround to get the message to go away, or someone there can notify ebay.de of the problem.
