i18n.getPreferredSystemLanguages()
Returns the preferred locales of the operating system. This is different from the locales set in the browser; to get those, use i18n.getAcceptLanguages.
Syntax
js
let preferredSystemLanguages = await browser.i18n.getPreferredSystemLanguages()
Parameters
None.
Return value
A Promise fulfilled with an array of i18n.LanguageCode strings.