Roswell is a command-line tool for managing Common Lisp implementations, scripting, and building executables. It provides a unified interface to install, switch between, and run multiple Lisp implementations (SBCL, CCL, Clasp, ECL, ABCL, etc.), and supports shebang-style scripts with a `ros` interpreter. The architecture is a hybrid: a C binary handles low-level system operations (download, extraction, process management, configuration), while Lisp scripts implement higher-level logic (installation recipes, version detection, image dumping, Quicklisp integration). Key entry points are `src/main.c` (C) and `lisp/init.lisp` (Lisp, invoked by the C binary). External dependencies include curl/libcurl, git, make, and patch. The codebase is well-structured with cross-platform abstractions (Unix/Windows), a custom cons-cell type for dynamic data, and a consistent command dispatch pattern. It is actively maintained with CI across Linux, macOS, and Windows, but relies on web scraping for version detection and uses autotools for build, which introduces some fragility.