Firefox no longer supports the use of Microsoft OneNote Web Clipper. The extension disappeared from my browser Sat, Jul 08, 2023.
The OneNote Web Clipper is now only supported for use in Microsoft Edge browser and that extension will not allow selection of Notebook or Section for the clipper.
Interesting, for those interested, here it is in the web-archive:
I wonder if it was official Microsoft addon and whether these two are official Microsoft accounts:
https://addons.mozilla.org/en-US/firefox/user/11789114/
https://addons.mozilla.org/en-US/firefox/user/12508863/
Too bad anyone can name their account “Microsoft” and look “legitimate”.
Note that if the addon was removed from your Firefox, it usually means it was malicious or that the author released “auto-uninstalling” update.
Check the about:addons page, it can show you blocked addons:
https://support.mozilla.org/en-US/kb/add-ons-cause-issues-are-on-blocklist#w_how-will-i-know-if-an-add-on-is-blocked
EDIT:
Here is the last “onenote_clipper-3.9.0.xpi” installation file I could find - but it’s hard to say if it will work, or for how long:
unzip_me.zip (1.3 MB)
This message from “https://www.onenote.com/clipper”
OneNote Web Clipper is no longer supported on Firefox browser and works best using a modern browser like Microsoft Edge.
It appears that Microsoft has removed the addin from Mozilla Firefox
Oh, that’s bad 
.
Seems like Microsoft has some lazy developers these days.
I don’t want to brag but my ScrollAnywhere addon works in Firefox, Chrome, Edge, Safari, Opera and even Thunderbird. All from the same code-base. So if they can’t support modern Firefox, then they are doing something wrong. Shame on them!
It can’t be understood, why is Firefox’s OneNote Web Clipper in the computer also deleted simultaneously? Firefox can directly delete local data stored by users without notification?
Yes they can, BUT they do it only when addon is marked as malicious.
If I remember correctly, in this case the addon author (Microsoft) released auto-uninstalling update. And sadly uninstalling addon deletes also local data.