SUMMARY
Google has started officially disabling Chrome Extensions that don't use the new Manifest V3 standard. As a result, the Chrome Plasma Integration Extension is no longer functional.

Seeing this in the Chrome dev build on desktop. (See attached screenshots.)

Link to extension: https://chromewebstore.google.com/detail/plasma-integration/cimiefiiaegbelhefglklhhakcgmhkai
KDE git repo for extension: https://invent.kde.org/plasma/plasma-browser-integration
KDE wiki page with link to extension page: https://community.kde.org/Plasma/Browser_Integration

STEPS TO REPRODUCE
1. Install the Google Chrome developer build (on arch, it's available from the AUR as "google-chrome-dev"
2. Install the Plasma Integration extension from the above link (if you are still able to, otherwise, you'll need to sideload a copy from the KDE git repo, or your distro's repo)
3. Navigate to chrome://extensions via the url box
4. Observe that it states that "Plasma Integration" has been disabled (see screenshot)
5. Clicking on the 3-dot menu for the entry offers you an option to "Find alternatives", however there are no KDE-related alternatives available

OBSERVED RESULT
Plasma Integration is automatically disabled by chrome, with no option to reenable, and the related functionality is not available anymore.

EXPECTED RESULT
It works.