We should add more details to the web app manifest file

https://developer.mozilla.org/en-US/docs/Web/Manifest

Most web browsers show the "application" tab with a panel for the "manifest".
Currently the site shows like this in Firefox:


https://developer.mozilla.org/en-US/docs/Web/Manifest/background_color
https://developer.mozilla.org/en-US/docs/Web/Manifest/short_name

And in the homepage HTML markup we have

``

https://developer.mozilla.org/en-US/docs/Web/Manifest/theme_color

For reference

https://web.dev/add-manifest/

Locate the web app manifest and the homepage HTML markup, then compare the current entries with the linked MDN documentation for background_color, short_name, and theme_color. The work is done when the manifest contains the requested details and the browser's manifest panel shows the intended information.

Written by the indexing model from the issue text.