Front End Frameworks
The Form.io AngularJS library has two versions. The original AngularJS based libraries (2.x) and the new Core Formio.js based libraries.
The angular-formio library is based on the form.io core libraries.
The Form.io React libraries come in two versions. The 1.x version is a renderer entirely built in React. The 2.x version is based on the Core Formio.js library.