[dilDDoS]

Their website is a bit confusing.

> Today, Ninja Cookie is not a free software and is not open-source. However, become a free and open-source software is a goal and we are working to achieve it. We hope that this will happen very soon.

versus

> In order to fund the development of Ninja Cookie, we will soon be offering a premium version.

Also, the author of the article seems to think the extension uses a blacklist content filter rather than "removing cookie banners by rejecting cookies" since they were still noticing cookie banners on some sites.

As a side note - at least on desktop, I think this is solved well enough by just using the element zapper in uBlock Origin. It only takes a couple seconds with a keyboard shortcut.