General
Changes apply immediately and are saved for next time.
Startup
Open previous windows and tabs
Restore the tabs from your last session when Theseus starts.
Appearance
Choose a theme for the browser. System follows your operating system's light/dark setting.
Search
Pick what your address bar and the toolbar dropdown search with.
Default search engine
Used when you type into the address bar.
Additional search engines
These appear in the toolbar dropdown. Drag to reorder. Toggle off to move an engine back to the catalog.
Add from catalog
Discover more engines
Or add a custom URL
Registries
How Theseus picks between the BCNR / BCDN and ICANN / IANA, when a name exists in both.
Collision policy
A name only exists in both registries when its TLD isn't BCNR-unique (e.g.
.de). BCNR-unique TLDs (that only exist on BCNR) never conflict.Remembered choices
"Always use …" picks you made from the switcher or the prompt. Reset them to be asked again.
Performance
Keep Theseus light on resources.
Throttle inactive tabs
Background and inactive tabs use far less CPU. Recommended.
Privacy
Reduce tracking and lock down device access.
WebRTC IP policy
Controls which IP addresses WebRTC may reveal — the same thing the "WebRTC Network Limiter" extension does, built in. Public interface only hides your local IP; Disable non-proxied UDP is strongest. Tor forces the strongest automatically.
Block camera
Deny camera by default — also hides its name from fingerprinting.
Block microphone
Deny microphone by default — also hides its name from fingerprinting.
Hide media devices
Blank the labels and IDs of all cameras, microphones and speakers from
enumerateDevices() — closes a WebRTC fingerprinting leak, like Firefox.Anti-fingerprinting
For each: Show (real), Hide (neutral value), Spoof (a decoy), or Manual (set your own).
Timezone
What sites read via JavaScript (Intl / Date).
Language
navigator.language and the Accept-Language header. Spoof reports a major world language; Manual lets you type any locale.
Location
Hide denies geolocation; Spoof reports a chosen region; Manual reports exact coordinates.
These reduce tracking and hide your IP, but a custom browser can still be fingerprinted. For maximum anonymity, use the Tor Browser.