It may be. The person saying that has contributed artwork but is not the maintainer. It is a bad look though. It sounds like they want to build the next release in secret so the fork can’t release features first.
Yeah. The maintainer said in their blog post they're looking for a license that lets people read the code but not fork it. Isn't that just standard American copyright?
Edit: Looks like they went with CC BY-NC-SA 4.0 Deed (Attribution-NonCommercial-ShareAlike 4.0 International). So not an open source license and one that CC themselves recommends not using for software.
Some time ago, a bunch of really smart people wanted to be able to modify software, so it can never be broken since they can fix it. Thus began open source, which is having a piece of software tell everybody exactly how to make it. Meanwhile, many companies don't want people to modify their software, usually because they don't want people easily competing with them and bankrupting them due to creating a better modification. Such software that isn't open source is termed "proprietary".
Floorp was one of these open source softwares. Some ambitious Japanese people modified Firefox, added some features and customizations, and named it "Floorp".
Recently, these people decided, for whatever reason, to stop the public from being able to access some of the materials and configurations for making Floorp. They did this by creating a new "warehouse" to store these materials, sealing off the access to it, and replacing the original location of the now proprietary materials with a note that tells you the location of the warehouse you can't get in.