What happens if I remove a user from "jira-user" in Jira?

[Miko Villa]

Will it remove everything that the user created/modified in a project? (i.e., issues, reports, screens, etc) TIA

[Aleks Yenin (Polontech)]

No, it won't. User just won't be able to log in if there is no user roles at all for this user

[Joe Pitt]

In a default install they won't be able to logon or count against your licensed number of users unless you've recreated another group with logon rights and put them in it.