This add-on takes you to a cloud based editor, as you do not know the provider it would not be a good idea to fill in forms that contain large amounts of personal information, such as bank details or tax codes.

For general stuff it's an OK solution, but you need to enable ads to allow it to work.

L'intégrateur dans le navigateur rend plus aisé l'édition du document

It requested I disable adblocker which I did as an exception but it didn't work. I then allowed ads via Ghostery, it still didn't work. I went into uMatrix and allowed some scripts but it still said i was running an adblocker(?). I refused to allow google tag manager scripts to run as I work with people's private information. So google trackers are out. I had to give up. If you value privacy this won't work it seems.

Does not work well with ABP/NoScript/uBlock
Huge problems in preserving initial formating - use it if you want your letters scrambled around: It should be called Format Obfuscator

Pointless, redirects you to a website, and it did not work (couldn't even open up my pdf file).

Ok

Like

I imagined that the extension would allow me to edit the PDF at the URL that's in the browser.

Instead, the extension seems to be primarily a link to http://www.redcoolmedia.net/onlineeditor/preloginpdfoffice.html

Maybe a great service (I didn't test it) but version 1.3.5 of the extension seems to do little more than can be done with a simple, traditional bookmark.