All, be vary careful, the last two updates have wasted a lot of my time. The first one trashed my last update. I'm having to completely re-develop.
The second one randomly freezes, losing any previous work. Save after every change!
IIRC, the order of event was...
1. Updated Flow, with SubFlow and other changes.
2. Ran, worked fine.
3. Next day, update notification. Ran Update.
4. Ran just updated Flow and....all changes lost.
This happened once before which is why I asked where the souce files are. Sorry, it's pretty user hostile to hide these or not provide a way to save locally. Not sharing is not caring!
Today, another update....
Twice, it got stuck in deep loop, any UI interaction would cause the (not responding) to appear for ~15 seconds. Closing was the only way out, no prompt or oppty to save.