Acknowledgements

What Hygieia is built on

Hygieia is almost entirely first-party Swift. What it does borrow is listed here in full, with the licence it is used under.

Third-party code

None

Hygieia compiles no third-party libraries at all. Crash reporting used to be the one exception — it was removed, and diagnostics are now written to a file on your own Mac instead of being sent to anyone.

A utility that asks for Full Disk Access and then reads every path on the volume is asking for a great deal of trust. Every dependency it ships is more code doing that on our recommendation rather than yours. The honest number is zero.

Apple frameworks

The rest is the system

Everything else is Apple's, shipped with macOS. Named here because which framework does what is the clearest answer to "where does my data go".

SwiftUI
The entire interface.
Vision
On-device feature prints for near-identical photo matching. No image ever leaves the Mac.
CryptoKit
SHA-256 hashing for exact duplicate detection.
StoreKit
Purchases on the Mac App Store channel.
ServiceManagement
Registering the login item for scheduled maintenance.
OSLog
Structured logging, with private data marked as such.
AppKit
Trash operations, Finder integration and window behaviour.
IOKit
Reading disk and volume information.
ImageIO
Reading image metadata without decoding whole files.
UniformTypeIdentifiers
Deciding what a file is by type rather than by extension.
Security
Keychain storage for the licence.

The name

Hygieia

Hygieia (hy-JEE-ah) was the Greek goddess of health, cleanliness and prevention — the daughter of Asclepius, and the root of the word "hygiene". She was worshipped for keeping people well rather than for curing them once they were not, which is roughly the job of a disk cleaner. The mark is a clinical plus for the same reason.