Answer by questionto42 for Not trusting file .hg/hgrc from untrusted user root, group dev

Not your case, but might be worth a hint:

I had this error in a local container that was setup to migrate repos from hg to GitLab. Solved it by just by changing the ownership of the .hg directory in the downloaded hg's repository folder to root user/group:

chown -R root:root .hg

And the message not trusting file /data/hg-repo/.hg/hgrc from untrusted user 1000, group 1000 was gone.