Its a Custom Web Component. Do not use the constructor directly with the new keyword. Instead, use one of the 3 following methods:

Create the Web Component and call its init method:

const myWizardPanel = document.createElement("a-wizardpanel").init(config)

Or use the shorthand for it:

const myWizardPanel = createWizardPanel({

  // Can have the same config properties as a panel
  title: "Setup"
  icon: "fas fa-wrench",
  headerBackgroundColor: "#00aaee",
  closable: true,
  draggable: true,
  modal: true,
  display: "flex"
  flexFlow: "column",
  padding: "10px",

  // Wizard pages
  items: [
     wizardPage1,
     wizardPage2,
     wizardPage3
  ],
  actionText: "Proceed",
  action: () => {
     // Perform action
  }
})

myWizardPanel.render()

Or directly declare the config inside a container component:

const myBlock = createBlock({
  items: [
      {
          type: "wizardpanel",
          title: "Foo",
          items: [
              wizardPage1,
              wizardPage2,
              wizardPage3
          ],
          actionText: "Proceed",
          action: () => {
             // Perform action
          }
      }
  ]
})
myBlock.render()