They've been developing a (first-party) extension that already supports about a dozen languages and does translations completely client-side: https://browser.mt

They've been developing a (first-party) extension that already supports about a dozen languages and does translations completely client-side: https://browser.mt/ https://browser.mt/ I'm assuming it's gonna merge into Firefox once they're satisfied with it. Also EU supported its early development, which I think is quite cool: https://cordis.europa.eu/project/id/825303 https://cordis.europa.eu/project/id/825303