Gulp is a streaming build system for automating development workflows. It provides a minimal API surface (src, dest, watch, task, series, parallel) that allows developers to define tasks as asynchronous functions and compose them into pipelines. The core library is a thin wrapper around several specialized modules: Undertaker for task orchestration, vinyl-fs for file I/O, glob-watcher for file watching, and gulp-cli for command-line interaction. The architecture is modular and dependency-heavy, with the main index.js file creating a Gulp instance that inherits from Undertaker and delegates file operations to vinyl-fs. The system is designed to be used programmatically or via the CLI, and it supports both CommonJS and ESM imports. The codebase is well-maintained and has recently undergone a major version 5 release with significant updates to stream handling, globbing, and dependency management.