Unlimited 'anonymous users' are permitted on all licenses. What the definition is of 'anonymous user

[Paulina Miskiewicz]

What permissions does the anonymous user have and does it limit to only one user?

[Nic Brough -Adaptavist-]

No, anonymous is not "one user". 

It means "anyone who has not logged in, so I do not know who they are".   Anonymous users can have full access, but I would very strongly recommend that you do not allow anything other than "browse project".   If your Jira is on the internet, not firewalled off, that's an absolute rule, because an anonymous access Jira on the internet rapidly becomes a spam machine.