Apple

FoundationDB - the open source, distributed, transactional key-value store

This maintains proposals for changes and user-visible enhancements to the Swift Programming Language.

The Foundation Project, providing core utilities, internationalization, and OS independence

The Swift Programming Language

This is the version of LLDB that supports the Swift programming language & REPL.

SwiftPM package for SwiftSyntax library.

The Package Manager for the Swift Programming Language

Event-driven network application framework for high performance protocol servers & clients, non-blocking.

Automated tests for validating the generated Swift snapshots behave correctly

The infrastructure and project index comprising the Swift source compatibility suite.

Official CUPS Sources

Plugin and runtime library for using protobuf with Swift

Turi Create simplifies the development of custom machine learning models.

The libdispatch Project, (a.k.a. Grand Central Dispatch), for concurrency on multicore hardware

Extensions for SwiftNIO to support Apple platforms as first-class citizens.

HTTP/2 support for SwiftNIO

Useful code around SwiftNIO.

A Logging API package for Swift 5.

TLS Support for SwiftNIO, based on BoringSSL.

A low-level build system, used by Xcode and the Swift Package Manager

The XCTest Project, A Swift core library for providing unit test support

Index database library for use with sourcekit-lsp

Language Server Protocol implementation for Swift and C-based languages

Logging and communication to allow Swift toolchains to communicate with Xcode.

Stress testing utilities for Swift's tooling