This ESLint plugin detects when a module is imported or required but not listed as a dependency in package.json, helping prevent accidental dependencies on modules installed deeper in the dependency tree. It's designed for Node.js developers who want to ensure their project's dependencies are explicitly declared and avoid runtime issues when dependencies are missing. The plugin can be configured to check various dependency types (dependencies, devDependencies, peerDependencies, optionalDependencies) and reports violations as errors.