The Examples for Developers project aims to provide high-quality, well-documented API examples for a broad range of Drupal core functionality.
The "Read from a file" feature implemented by the file_example submodule can be used to expose any file that PHP can access. Therefore, the file_example sub-module is being removed from Examples for Developers until a version demonstrating file security best practices can be added back in the future. Developers who based a new module on this example should review their code for an access bypass.