Microsoft removed their Extension for Firefox and even made a extension update that uninstalled the extension from Firefox and removed the OneNote data.

Microsoft apparently only wants to support their Microsoft Edge web browser with OneNote, so they can get more of your data.

Hmmm. Thanks. Trouble is I am heavily invested in OneNote and I'm a frequent web clipper so does this development mean there is no workaround?

See also:

• https://discourse.mozilla-community.org/t/onenote-web-clipper-extension-has-been-removed-from-firefox/120910

The Microsoft message of "OneNote Web Clipper is no longer supported on Firefox browser and works best using a modern browser like Microsoft Edge." is hilarious when Edge is a rather young web browser compared to the Mozilla Firefox browser as it came out as (first original name of) Phoenix 0.1 way back on September 23, 2002 while Edge started out much more recent on July 29, 2015.