I got a message this morning about reputation changes, stating they were due to a user being removed. However, there is no information which user that was. Is there any way to find out?
Also, this Q&A seems to indicate that reputation changes only happen when a user was removed for fraudulent voting, but the message itself linked to a help page that states votes can be undone if a user is removed for any cause. Which of the two is correct?
There shouldn't be any easy way for a non-moderator to determine which user was removed. With some investigation it might be possible to determine it but I'd discourage you from doing so.
Moderators can access deleted user profiles and can see when/why they were deleted. However that is privileged information and we aren't able to share it with non-moderators. Hence why I'd prefer you don't spend too much effort trying to uncover this information.
Whether or not the votes are reverse depends on the number of votes cast by the user. If a user that has cast a lot of votes is deleted they often don't reverse the votes as it might result in large reputation drops for other users. See this main meta for details.
If you're seeing a reputation change due to "User was removed" then the user that was removed had not cast a particularly high number of votes and the net effect on reputation from reversing them is minimal.
