It is not yet open source. I was reading their Terms recently with the same question. I am not sure why it is so popular even though it is a closed ecosystem. Seems to be an odd choice for any sovereign individual's use. https://www.fountain.fm/terms-of-use

Faster than a planned demo

Oh my gawd! You use CAD instead of USD and think GBP is a shitcoin? Oh my gawd! You would trade bananas for apples instead of bartering with clay? Shitcoiner! Emotional faggots think this way.

People who offer no unique insight or perspective are the most easily forgotten.

It's pathetic how many people are willing, desirous even, of being energetically vacant. No imagination, no Will to Live, afraid they may come apart if ideas are challenged. Maybe it's a phenomenon of the current Time, disgusting.