browser.webNavigation.onCreatedNavigationTarget.addListener(
  listener,                   // function
  filter                      // optional object
)
browser.webNavigation.onCreatedNavigationTarget.removeListener(listener)
browser.webNavigation.onCreatedNavigationTarget.hasListener(listener)

Events have three functions:

addListener(callback)

Adds a listener to this event.

removeListener(listener)

Stop listening to this event. The listener argument is the listener to remove.

hasListener(listener)

Check whether listener is registered for this event. Returns true if it is listening, false otherwise.

callback

Function that will be called when this event occurs. The function will be passed the following arguments:

details

object. Details about the navigation event. See the details section for more information.

filter Optional

object. An object containing a single property url, which is an Array of events.UrlFilter objects. If you include this parameter, then the event will fire only for transitions to URLs which match at least one UrlFilter in the array. If you omit this parameter, the event will fire for all transitions. Note that filter is not supported in Firefox.

sourceFrameId

integer. ID of the frame from which the navigation is initiated. 0 indicates that the frame is the tab's top-level browsing context, not a nested <iframe>. A positive value indicates that navigation is initiated from a nested iframe. Frame IDs are unique for a given tab and process.

sourceProcessId

integer. The ID of the process from which the navigation is initiated.

sourceTabId

integer. The ID of the tab from which the navigation is initiated. For example, if the user opens a link in a new tab, this will be the ID of the tab containing the link.

tabId

integer. The ID of the newly created tab.

timeStamp

number. The time when the browser created the navigation target, in milliseconds since the epoch.

url

string. The URL which will be loaded in the new tab.

windowId

number. The ID of the window in which the new tab is created.

Logs the target URL, source Tab ID, and source frame ID for onCreatedNavigationTarget, if the target's hostname contains "example.com" or starts with "developer".

const filter = {
  url:
  [
    {hostContains: "example.com"},
    {hostPrefix: "developer"}
  ]
}

function logOnCreatedNavigationTarget(details) {
  console.log(`onCreatedNavigationTarget: ${details.url}`);
  console.log(details.sourceTabId);
  console.log(details.sourceFrameId);
}

browser.webNavigation.onCreatedNavigationTarget.addListener(logOnCreatedNavigationTarget, filter);