It was a free speech subreddit that discussed immigration freely.
Reddit admins hired somebody yesterday to increase our safety for us. https://archive.is/SCJyy
r / european played a semi-major role in signal boosting the Cologne Sex Attacks back in January; as did TRP. Mainstream subs were forced to stop removing/deleting threads as there was so much attention on them. Then it was frontpage. Then the news on reddit helped signal boost the message on twitter; which eventually lead to (some) news organisations finally reporting on the story 4 days after it happened. Then that got the ball rolling on opening up the Overton window.
Daily mail reporters and Breitbart reporters used the european sub to crowdsource local news on attacks that national publications (of Germany, Sweden, etc) refused to print. I know this as I know people working there. They did not have systems to crowdsource the local news stories in many languages. It was a small sub but it helped changed the narrative at a global scale for a few months.
Be very careful about sharing your email with reddit if you plan to view this or any quarantined sub. They removed their disclaimer about sharing data with governments in the ToS a few months back.
For a long time FatPeopleHate, european and theredpill were considered by many as the holy triad of reddit 'hatespeech'. Now only one is left.
There might be a high risk of this sub also getting quarantined shortly.