trouble with i18n loading correct locale

[pmnzt]

it seems i18n does not just use cookies to save the locale even thought i enabled cookies in the config.

detectBrowserLanguage: {
      useCookie: true,
      cookieKey: 'i18n_redirected',
      redirectOn: 'root',  // recommended
    }

if i remove the cookies it still default to some locale!.

only when opening a private window things look like they were the first time you open the site.

But where else does i18n store the preference?.