A new memorial was revealed recently:
https://www.dawn.com/news/1695545/norway-inaugurates-utoya-massacre-memorial
I propose to add it to the OSM map: problem is the exact location, which is unknown to me.
Checking the news reports and pictures on Google, then the new memorial seems to outlook at another island. That would position it to the north of Utoya. The location of this Note would also be a logical place. Tnx.