The difference between free software and open source software is not the percentage of proprietary stuff left in the software, but the philosophy behind it. Open source is only about the possibility to few the source code and help improve the software. Free software is about the freedom to view the code as one of I think 4 essential freedoms defined.
As I said. I have discussed this topic (Free Software versus Open Source) with Richard Stallman in person. Now tell me what in the Firefox client is not Open Source?
You have full access to the code, you are entitled to change anything you like, and you are entitled to redistribute with or without your change. You may also fork Firefox, which has happened numerous times. So where does this philosophy fall behind the philosophy of Open Source.
That the Mozilla foundation bought the proprietary Pocket is something I agree is questionable. But for other reasons (they never asked their users), but it does not change anything of what I wrote above. The code of the client is still Open Source, only the server part of Pocket is proprietary and that is not part of the client.
I have been a tech journalist for over a decade. I have never ever seen anywhere a discussion that Firefox allegedly wouldn’t be Open Source.
I agree it is not Free Software, but that is not the point.
““Mozilla Firefox in contrast is 100 per cent open source,” Eich wrote, by way of tooting the nonprofit’s own horn.”