The All reports tab, on the Reporting (Beta) screen, is only available to site admins, and allows them to access all the reports that have been created on the platform, including those created by other users.
As well as being able to view the reports created by other users, site admins can also manage them, including being able to:
Note: The ability to access certain tabs and features in the Reporting (Beta) screen depends on your user type and selected permissions. For information on which tabs and features are accessible to each user type in the Reporting (Beta) screen, see Which features and tabs do I have permission to access on the Reporting (Beta) screen?.