Privacy

Ubuntu and the browsers phone home by default. Ombuntu turns that off, and tells you exactly what it changed.

Every change is a config file or a service state, listed here with its location so you can reverse any of them. Running the installer again re-applies the set.

Canonical and Ubuntu

Crash reporting. apport is disabled (/etc/default/apport) and whoopsie, the uploader, is removed. ubuntu-report, popularity-contest and kerneloops are removed if present.
Ubuntu Pro adverts. Off in the login message (/etc/default/motd-news) and in apt output (pro config set apt_news=false). The Pro timer is disabled.
Desktop statistics. Usage statistics and problem reporting are off in the GNOME privacy settings that GTK apps read.

Firefox

A policy file at /etc/firefox/policies/policies.json, which the snap reads too: telemetry, Firefox Studies, Pocket, sponsored tiles and suggestions, and recommendation nags are off; tracking protection is strict with cryptomining and fingerprinting blocked.

Chrome, Chromium, Brave, Edge, Vivaldi

A policy file in each browser's managed-policy directory (for example /etc/vivaldi/policies/managed/): metrics reporting, URL-keyed data collection, extended Safe Browsing reporting, cloud spell-check, address-bar search suggestions, alternate error pages, link prefetching, promotions, surveys, shopping features and the Privacy Sandbox ad APIs are off. Field-trial fetching is limited to critical fixes. Edge additionally has diagnostic data and personalisation reporting off.

Saved passwords are stored with the GNOME keyring rather than a plain-text fallback, because Ombuntu launches browsers with the keyring backend selected.

Developer tools

DO_NOT_TRACK=1 and the opt-out variables for .NET, Next.js, Nuxt, Astro, Gatsby, Homebrew, PowerShell, Azure CLI, AWS SAM, Stripe CLI and Hugging Face are set in the session and shell. VS Code and Zed installed from the menu get telemetry off in their settings.

Left alone, and why

snapd talks to the Snap Store; that is how the Firefox snap updates.
NetworkManager's captive-portal check contacts connectivity-check.ubuntu.com when a network comes up. It is what makes hotel Wi-Fi login pages appear. Disable it with a [connectivity] enabled=false NetworkManager config if you prefer.
Vivaldi sends its own anonymous usage-count ping, which has no policy switch.
apt downloads package lists from Ubuntu mirrors.

Security choices

Root is used for three things: apt, Signal's apt repository, and the login session file.
Every download is pinned and checksummed; a mismatch aborts the install.
Omarchy's plugins are disabled: hooks, menu extensions and remote theme installs all run arbitrary code with your user rights.
Passwordless sudo, autologin and installers that pipe remote scripts into a shell are not offered.