Correction: the app itself doesn’t appear to be free/open (which is fine, it’s still an indie app and that definitely counts) although the interface library and some other components appear to be.
I also just wrote an email to the author to both praise him for making what is one of the most gorgeous apps I’ve seen in a long while and to ask what his plans are for the future.
I‘d love to see, for example, some EU funding being used to contribute this to the commons.
@aral It's a bit more discriminatory. If you open the page with Safari, the only option is to buy the app. No editor. If you open the page with Chrome, it shows. That's kinda harsh, IMHO. Browser is browser. A website shouldn't reduce functionality just to sell the app. IMHO.
For people who care about, support, or build Free, Libre, and Open Source Software (FLOSS).