This repository is the formal specification and standard library for the Dhall configuration language. Dhall is a programmable, non-Turing-complete configuration language designed to generate JSON and YAML. It features a strong static type system, imports with integrity checking (SHA-256), record merging, and a comprehensive standard library (Prelude) covering common data types and operations. The repository includes a reference implementation in Haskell (parser, type checker, normalizer, binary encoder/decoder), an extensive test suite, and infrastructure for building and deploying the language ecosystem using NixOps. The architecture is centered around a formal semantics defined in literate Haskell and Markdown, covering syntax, alpha-normalization, beta-normalization, type inference, import resolution, and binary encoding. The Prelude is a collection of Dhall source files that provide reusable functions following functional programming patterns. The test suite is organized by language feature and includes success/failure cases for parsers, normalization, type inference, imports, and binary decoding. Key components include the parser (standard/Parser.hs) using Megaparsec combinators, the beta-normalization specification (standard/BetaNormalization.lhs), the Prelude standard library (Prelude/), and the NixOps deployment configuration (nixops/). The repository is actively maintained with regular releases and a detailed changelog.