Screenshot / Code Snippet
Now and then, Stack Exchange wants our attention for new blog posts or other important announcements. One of the ways is a banner just below the top bar, which is fine ... until you realize you have to dismiss it on every. single. site. This script aims to solve this problem; once you dismiss the banner on one site, it will automatically dismiss it on all other sites in the network.
It's a userscript which means you need a userscript manager installed in your browser if you don't have one already. Just Google for Violentmonkey or Tampermonkey, how to install them depends on your browser.
Tested with Violentmonkey in Firefox and Tampermonkey in Chrome on macOS, but it's likely to work on all browsers and platforms. (Please let me know if it doesn't!)
Post a comment or answer here, or create an issue/pull request on GitHub.