legal · third-party

Third-party licenses

Last updated: August 5, 2026

z3.run is proprietary software built on excellent open-source components. This page records the parts we redistribute or link, their licenses, and the notices those licenses require — including a written source offer for the Linux guest kernels. It mirrors the THIRD-PARTY.md file shipped with every self-hosted package.

1. Bundled in the platform

These ship as files inside a z3.run production package and run on the host.

Component	Version	License	Copyright
Firecracker + jailer	v1.12.1	Apache-2.0	© Amazon.com, Inc.
Linux kernel (guest — base & TUN)	6.1.128	GPL-2.0-only	Linux kernel authors — see §2
Nebula (overlay VNet)	v1.10.3	MIT	© Slack Technologies, Inc.
libmsquic (QUIC federation)	2.5.x	MIT	© Microsoft Corporation
z3dev server, guest-agent, wrap	—	proprietary	© z3.run

The z3dev binaries are compiled Native-AOT and statically embed the .NET runtime, musl libc and zlib — all permissive (MIT / MIT / zlib).

2. Linux kernel — GPL-2.0 source offer

We redistribute two Linux kernel binaries (vmlinux, vmlinux-tun), licensed under GPL-2.0-only. We do not modify the kernel source; vmlinux-tun differs from stock only in build-time .config options (built-in TUN, CIFS, BBR, fq, virtio-balloon). Complete corresponding source:

Kernel source: vanilla Linux 6.1.128 from kernel.org.
vmlinux config: the Firecracker CI microVM config, unmodified.
vmlinux-tun config: that CI config plus the deltas listed above; the exact .config ships in the package as fc/vmlinux-tun.config, so the build is reproducible.

Written offer: for any binary in a z3.run production package, we will provide the complete corresponding source for the GPL-2.0 components on request for three years, at no charge beyond the cost of distribution. Contact legal@z3.run.

3. Server & UI dependencies

Server (NuGet, linked into the AOT binary): Konscious Argon2/Blake2, MessagePack, Microsoft.Data.Sqlite, Microsoft.NET.StringTools, System.IO.Hashing — MIT; the SQLitePCLRaw packages — Apache-2.0; the SQLite engine itself is public domain; the .NET runtime/BCL — MIT.

Web UI (npm, compiled into the bundle): React, React-DOM, React-Router, xterm.js and their entire resolved dependency tree are permissive — MIT, ISC, BSD-3-Clause, Apache-2.0, and CC-BY-4.0 (browser-support data). No copyleft is present. Fonts and icons on these public pages are loaded from Google Fonts / cdnjs at runtime and are not redistributed by z3.run.

The dah harness (dah.py, the connector you run on your computer and the design-agent VM runs): z3.run's own source, using the Python standard library only. For the encryption it uses the cryptography package (pyca, Apache-2.0 OR BSD-3-Clause): when it is missing, dah.py connect installs it from PyPI with your own pip (DAH_NO_INSTALL=1 skips that, and dah then uses its own pure-Python code). It is not bundled or redistributed by z3.run.

4. Host runtime tools

On first run the host installs skopeo, umoci, e2fsprogs, xfsprogs, nftables, haproxy and cryptsetup from the operating system's own package repositories. These are separate programs invoked as subprocesses — not linked into z3dev — so their licenses (a mix of GPL / LGPL / Apache / BSD) do not extend to z3dev. Air-gapped packages that bundle these GPL/LGPL tools carry the same source-availability offer as §2; their source is available from the OS archive the package was built against.

5. Full license texts

The complete Apache License 2.0 and MIT License texts, with each component's copyright holder, are included in the THIRD-PARTY.md file shipped in every self-hosted package. The GPL-2.0 text accompanies the kernel source tarball above and is published at gnu.org.