Donationware: you must donate to use it. Not like regular optional donates.
I dunno this lacks nuance… I think this could easily be referring to different economic situations. The concept of donation usually has this implication of not being a for-profit entity or for a indie developer’s side project. These kinds of apps usually are still either open source or source available which is different than closed, proprietary applications. With this focus on money, I would assume that “free” is meaning gratis where users can often be the product & while the source is not available …or some VC-funded product where they are loss-leading a free tier now just eventually charge everyone later which is hardly good, with a dash of open washing to taste.