This CN banner includes FB and Twitter share links:
UPDATE: Ooop, previously I put the wrong banner link here. This is the correct one.
At first glance, it seems acceptable, since it doesn't seem to download any images from external sites. Interaction with FB and Twitter only happens when the user clicks.
It also seems that in the referrer header, those sites will only get the domain the banner was seen on (en.wikipedia.org) and not the name of the article the user was browsing, due to referrer policy. However, I'm also not sure if this works everywhere. See T180921.
Any additional feedback would be much appreciated. Many thanks in advance!!!