Every path, in writing.

What it is

Build files and search indexes Xcode creates while compiling and browsing your projects. Xcode's own build tool describes this location as where “build products and other derived data” go (xcodebuild -help).

If removed

Source code, git history and project settings are not stored here, so a normal project loses nothing you cannot rebuild. The effect is that the next build of each affected project is slower while Xcode recompiles and re-indexes. If a project uses a custom build script that writes its own output into DerivedData, that output is removed too.

Get it back

Open the project in Xcode and build it (Product → Build, ⌘B), Xcode recreates DerivedData automatically. From Terminal, the equivalent is: xcodebuild build (run from the project directory).

Verified by

locally tested

Last checked on

macOS 26.6.2, Xcode 26.6

Made by

Xcode

This rule's own page, with each tool's commands

Made by

Xcode

Made by

Xcode

Made by

Xcode Simulator

Made by

Xcode

What it is

Package files npm downloads and keeps so it doesn't have to fetch them again on your next install. npm's own documentation (npm help cache) describes this as a content-addressable cache of “http request data as well as other package-related data.”

If removed

The next time you install a package that was cached here, npm downloads it from the registry again, that install is slower and needs an internet connection. Packages already installed into a project's node_modules folder are not touched.

Get it back

Run npm install in any project that needs it, npm re-downloads what's missing and rebuilds the cache automatically, though a package version that has since been unpublished from the registry may not come back.

Verified by

vendor documentation

Last checked on

macOS 26.6.2, npm 10.9.3

Made by

npm

This rule's own page, with each tool's commands

Made by

npm

Made by

Homebrew

What it is

Crate archives Cargo downloads from crates.io, the sources it unpacks from them, and its copy of the registry index, kept so builds don't fetch them again.

If removed

The next build of any Rust project downloads the crates it needs again, that build is slower and needs an internet connection. Compiled output in a project's target folder is not touched.

Get it back

Run cargo build (or cargo fetch) in any project, Cargo downloads what is missing by itself. A crate version that has since been yanked or removed from the registry may not come back.

Verified by

vendor documentation: The Cargo Book, “Cargo Home”, section “Clearing the cache” (https://doc.rust-lang.org/cargo/guide/cargo-home.html), “you can always remove any part of the cache”. Recreation proved in a scratch CARGO_HOME on 10 Oct 2026 with cargo 1.97.1: registry deleted, cargo build downloaded and unpacked it again.

Last checked on

macOS 26.6.2, cargo 1.97.1

Made by

Cargo

This rule's own page, with each tool's commands

Made by

rustup

What it is

Downloads pip has made and wheels it has built, kept so the next install doesn't fetch or build them again.

If removed

The next pip install downloads packages again, and rebuilds any wheel it had built, slower, and it needs an internet connection. Installed packages are not touched.

Get it back

Nothing to do, pip fills the cache again the next time it installs something.

Verified by

vendor documentation: pip documentation, “Caching”, section “Cache management” (https://pip.pypa.io/en/stable/topics/caching/), pip's own command “pip cache purge” clears every file from this cache. Recreation proved in a scratch PIP_CACHE_DIR on 10 Oct 2026 with pip 25.2: cache deleted, pip download filled it again.

Last checked on

macOS 26.6.2, pip 25.2

Made by

pip

This rule's own page, with each tool's commands

Made by

conda

Made by

Swift Package Manager

What it is

Every package version pnpm has downloaded, kept once so each project can share it instead of storing its own copy.

If removed

Projects that are already installed keep working. pnpm downloads a package again the next time a project needs one it doesn't have.

Get it back

Nothing to do, pnpm refills the store as projects need packages.

Verified by

vendor documentation and local test: pnpm documentation, “pnpm store”, section “prune” (https://pnpm.io/cli/store), “pnpm will download them again”; and the FAQ on the store and node_modules (https://pnpm.io/faq). Proved in a scratch store on 10 Oct 2026 with pnpm 10.17.0 (files cloned into node_modules on APFS): store deleted, then the project's code, pnpm install, pnpm add and pnpm install --frozen-lockfile each ran with exit 0 and no prompt.

Last checked on

macOS 26.6.2, pnpm 10.17.0

Made by

pnpm

This rule's own page, with each tool's commands

What it is

The model files Ollama downloaded so it can run an AI model locally on this Mac, without sending anything over the network.

If removed

The named model is removed and has to be downloaded again before anything that uses it can work, or built again, if you made it yourself with `ollama create`. Model sizes vary widely, from under 100 MB to tens of gigabytes; check this specific model's size in Spaceific before removing it.

Get it back

Run: ollama pull <model>:<tag> (for example, ollama pull qwen2.5:3b). For a pinned tag like that, you get back the exact version you had. For a :latest tag, you get whatever the current version of that model is right now, not necessarily the identical bytes you deleted, since :latest can change over time.

Verified by

locally tested

Last checked on

macOS 26.6.2, Ollama 0.33.3

Made by

Ollama

This rule's own page, with each tool's commands

Made by

Hugging Face

Made by

EasyOCR

Made by

Cursor

Made by

Codeium

Made by

GitHub Copilot

Made by

Gemini

Made by

Codex

Made by

Antigravity

Made by

Antigravity

Made by

Cagent

What it is

Puppeteer's own private copy of the Chrome browser, downloaded so it can automate a browser without depending on one already being installed. Puppeteer's documentation states browsers are cached at exactly this path since v19.0.0.

If removed

Puppeteer re-downloads its private copy of Chrome the next time a project needs it, which requires an internet connection and can take several minutes. Until that download finishes, anything using Puppeteer fails to launch a browser. Check this folder's size in Spaceific to see how much has to come down again.

Get it back

Run: npx puppeteer browsers install

Verified by

vendor documentation

Last checked on

macOS 26.6.2, Chrome for Testing 150.0.7871.24

Made by

Puppeteer

This rule's own page, with each tool's commands