From the article: > Since Firefox 136, developers will see a console warning for h1s in article/aside/nav/section without author-defined font-size or margins

From the article: > Since Firefox 136, developers will see a console warning for h1s in article/aside/nav/section without author-defined font-size or margins Seems like it should be fairly obvious for any dev that tries to look into it even if they're not part of the cohort with the new behavoir.