What do you all think about adding something regarding tools that folks can use to preview content for mobile devices. Assuming of course that some folks might not have access to a mobile device. Things like desktop Chrome's "Device toolbar" and Safari's "Responsive design mode". As a tech-savvy person I've learned of things like this over time, but for editors I don't want to assume folks know these are available. Letting them know of tools they might already have at their finger tips might make it easer for folks to act upon these recommendations.
Topic on Talk:Recommendations for mobile friendly articles on Wikimedia wikis/Flow
We definitely need this. I don't think a mobile preview is useful, but certainly a browser extension could help here.
I've pitched a linter/editor warning built into MediaWiki along those lines here and am trying to win backing to make this a reality: https://phabricator.wikimedia.org/T200880
Just to throw another tool in the mix, m:User:Brion VIBBER/mobile-sidebar.js does a good job for some folks as far as I know.