This looks identical to the Sencha products [0]. Especially, their ExtJs framework [1].
Both the name and even their examples [2] look practically like copies. Although, ExtJs does seem more fleshed out and way more full fledged [3]. They seem to have bindings with other frameworks too, like React and Angular [4].
The ExtJs framework started as an open source project ages ago. Is this some kind of a fork from then?
[1]: https://www.sencha.com/products/extjs/
[2]: https://examples.sencha.com/extjs/7.2.0/examples/kitchensink...