Hello, could not find where to translate this https://testpilot.firefox.com/experiments/containers on Pontoon so translated the strings as a Github issue https://github.com/mozilla/testpilot-containers/issues/528

That experiment is not localizable per developers' choice. I honestly expected it to be completely in English though, but that's still not a Firefox bug. Containers is a feature available within Firefox, I assume it will be updated once the experiment graduates, based on its results.