The address https://kiegroup.github.io/kogito-online/ gets 404. Where? Has it been removed? The source is here: https://docs.kogito.kie.org/latest/html_single/ I was using it before.
Business Modeler online viewer: Enables you to view and design BPMN and DMN models online at https://kiegroup.github.io/kogito-online/. The online modeler supports the .new format, so you can also enter bpmn.new or dmn.new in a web browser to start designing a new BPMN or DMN model in the online modeler.
Business Modeler standalone editors: Enable you to view and design BPMN and DMN models embedded in your web applications. To download the necessary files, you can either use the NPM artifacts from the Kogito tooling repository or download the JavaScript files directly for the DMN standalone editor library at https://kiegroup.github.io/kogito-online/standalone/dmn/index.js and for the BPMN standalone editor library at https://kiegroup.github.io/kogito-online/standalone/bpmn/index.js.
I'm new to the Kogito scene, so I haven't heard about Kogito Online but I think you might be referring to what is now called the Kie Sandbox?
Link: https://sandbox.kie.org/#/
Here's an article about it: KIE SANDBOX: TOP 7 KEY NEW FEATURES