I made this suggestion elsewhere but I believe it to be such a good one that it deserves its own thread.
To generate revenue to keep Xwidget engine funded I think you should add a donation link to the engine just as I do to each of my widgets. A simple donation link to paypal or similar. Plus another explaining what the donations are for, cost of domains, hosting &c.
An example:
Better still offer a fully fledged IDE for £25-£45. I would have paid that much for the right to develop using a decent IDE or perhaps even the option to build a closed and or compiled package. Something like that, an extra benefit that can cause some income.
Personally I would suggest improvements to the IDE to bring out a more advanced version. A basic one for standard use and extra functions for advanced developers like Jim and myself that want a dedicated IDE for widget development.
An alternative would be to research patreon for obtaining patrons to regularly fund Xwidgets, I would become one if I knew more about the development path for Xwidget and what exactly was going to come next.
Another alternative would be a kickstarter to help you complete the next revision.