What is the WordPress `DISALLOW_FILE_MODS` constant and how does it interact with plugin and theme installation security?

Question

WordPress Expert — Hard

What is the WordPress `DISALLOW_FILE_MODS` constant and how does it interact with plugin and theme installation security?

Accepted Answer

When the WordPress `DISALLOW_FILE_MODS` constant is set to true in wp-config.php, it prevents any file system modifications, including plugin/theme installation and updates. This is crucial for enforcing a read-only filesystem policy in production environments.