It looks like it's meant to be a building outline, but I don't want to destroy my whole base to find out. I tried leveling the ground on this same stone ring in an identical seed, but the outline wasn't there. Anybody know what it's about?
If you want to (maybe?) see for yourself, seed: ggddhf2ez
Source: https://www.reddit.com/r/valheim/comments/10bw97b/an_outline_appeared_as_i_was_leveling_the_ground/