For the bug tracker Mantis to allow anonymously browsing trackers etc you will have to create an account which will be a placeholder for all those people who are not logged in.
Best name it “anonymous”
Then, into your config_inc.php put:
# --- anonymous login ----------- $g_allow_anonymous_login = ON; $g_anonymous_account = 'anonymous';
And you’re done.
The rest is setting up permissions for the user anonymous / his group.