I’ve translated many MDN pages into Japanese, and I sometimes feel it’s hard to follow whether the each page is updated, though I subscribe some English pages with MDN feature.
So, I’ve created an add-on to check the localized MDN page is updated:
https://github.com/Uemmra3/mdn-l10n-update-checker
Maybe this add-on is useful for not only MDN writers, but also MDN readers.
Please try this, and any feedback is welcome!