It is a language server for Starlark with customized Kurtosis specific intellisense. You can learn more about about the Language Server Protocol(LSP) here and learn more about Starlark here.
Acknowledgments
This starlark-lsp was intially forked from tilt-dev/starlark-lsp which is licensed as Apache 2.0 license. The starlark-lsp has been extended to support Kurtosis built-ins.