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.

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.
System-wide resolver — Ariadne's Thread
A local daemon that resolves BCDN names for every browser on this machine (Chrome, Edge, Firefox, etc.), not just Theseus. Turning it off means non-Theseus browsers stop resolving .bch / .x / other BCNR TLDs; Theseus keeps working either way, since it has its own built-in resolver.
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