https://extensions.gnome.org/about/#no-detection would be more useful like this:

- "check to" can be removed from "check to make sure"

- "plugin" should be replaced by "browser extension", to make it clear beyond doubt it's a plugin for the browser, see the term used in https://en.wikipedia.org/wiki/Web_browser#Extensibility

- "and enabled in your browser preferences" should be a sentence of its own:
Make sure it's enabled in your browser preferences.

- Links to the actual browser extensions should be added, for example:
The "GNOME Shell Integration" browser extension is available in the <a href="https://chrome.google.com/webstore/detail/gnome-shell-integration/gphhapmejobijbbhgpjhcjognlahblep">Chrome web store</a>, etc.

- "or click-to-play is turned off entirely" suggests the user to disable a security measure, it should be removed. 


- "Some distributions don't quite package GNOME correctly. Make sure that you have the unzip package installed." should be removed. An error message should appear in the page when unzip is not available, or other error occurred.


- "Looking Glass" should be linked to a page which describes it, for example https://wiki.gnome.org/Projects/GnomeShell/LookingGlass

BTW, if you're at it, it would also be useful if the "Installed Extensions" in the section below is linked to https://extensions.gnome.org/local/