Preflight's core promise is that nothing about your build leaves your machine. This document spells out what that means and why you can rely on it.

Preflight opens the build artifact you point it at and reads:

• the app Info.plist,
• any PrivacyInfo.xcprivacy privacy manifests,
• the Frameworks directory listing,
• (optionally, opt-in) the app icon image.

It does not read anything outside the build artifact and the temp dir it creates for .ipa extraction.

The Preflight library imports Foundation and ZIPFoundation only (plus an #if canImport(ImageIO) guard for icon extraction). ZIPFoundation is a pure-Swift, cross-platform unzip library that reads and writes files — it does no networking. There is no URLSession, no socket, no HTTP, no DNS, no analytics, no crash reporting, no telemetry of any kind. It cannot contact App Store Connect, an LLM, or any server, because no such code exists in the package. You can verify this by grepping the sources.

These are deliberately absent from this package. The core never authenticates, never holds a key, never sends facts to a model. Because Preflight cannot read your ASC privacy labels, it is careful to never assert that something is "missing" from them — it only reports what your build embeds, leaving the cross-check to you.

Preflight never runs the app executable or any code from the build. It only parses data files (PropertyListSerialization on plists, a directory listing for frameworks, image decoding for the optional icon). There is no dlopen, no Process invocation of the build, no script execution — and no subprocess at all.

Unzipping an .ipa into a temp directory is done in-process by ZIPFoundation (pure Swift, cross-platform) via the default ZipExtractor — it reads the archive's bytes and writes the extracted files, never executing anything. This is isolated behind the ArchiveExtractor protocol so it can be swapped or audited independently.

For .ipa parsing, Preflight creates a unique temp directory under the system temp location, extracts into it, and removes it via defer — on success and on every failure path. No extracted build contents are left behind.

• The integrity of the build you hand it (it trusts the file you point at).
• Anything a downstream consumer does with the resulting BuildFacts/[Finding] (e.g. if your app then sends them somewhere — that's your code, not Preflight's).

The package is small, with a single dependency (ZIPFoundation, pure-Swift unzip). To verify the network claim:

grep -rEi 'URLSession|http|socket|Network|telemetry|analytics' Sources/

This should return nothing in Sources/Preflight (the README and docs mention the absence of these, which is expected).