There is an slightly fixed version here:
https://github.com/bhdouglass/cordova-ubuntu (based on Cordova 4.8?)
From @bhdouglass

and an App that still uses it:
https://github.com/milikhin/seabass
https://open-store.io/app/seabass.mikhael

And according to the official Cordova documentation support was dropped sometimes between version 7.x and 9.x:
https://cordova.apache.org/docs/en/7.x/guide/platforms/ubuntu/index.html
https://docs.ubuntu.com/phone/en/apps/html-5/guides-cordova-guide

I know that UT has it's own simple way of running webapps, but running offline HTML5 apps with some advanced features is quite a pain in it, and many advanced web-apps (uMastonauts etc.) are trying to make their own qt based wrappers, basically re-implementing a large part of what Cordova could offer.

In addition Cordova apps are much more easily portable between platforms (Android / iOS) and there is even a recent electron based Desktop support for it. Yes, hybrid apps have disadvantages, but they also have many positive aspects... no need to discuss this here

So maybe this would be worth picking up again and maybe even get upstream support? I guess they mainly dropped it because there was no maintainer for it, so is there anyone in this community interested (and with the skills)?