browser.declarativeNetRequest.onRuleMatchedDebug.addListener(listener)
browser.declarativeNetRequest.onRuleMatchedDebug.removeListener(listener)
browser.declarativeNetRequest.onRuleMatchedDebug.hasListener(listener)

Events have three functions:

addListener(listener)

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 is called when this event occurs. The function is passed these arguments:

request

An object containing information about the request the rule matched.

documentId Optional

A string. The unique identifier for the frame's document, if this request is for a frame.

documentLifecycle Optional

A string. The lifecycle of the frame's document, if this request is for a frame. Possible values are: "prerender", "active", "cached", or "pending_deletion".

frameId

A number. The value 0 indicates that the request happens in the main frame. A positive value indicates the ID of a subframe where the request happens. If the document of a (sub-)frame is loaded (type is main_frame or sub_frame), frameId indicates this frame's ID, not the outer frame's ID. Frame IDs are unique within a tab.

frameType Optional

A string. The type of the frame, if this request is for a frame. Possible values are: "outermost_frame", "fenced_frame", or "sub_frame".

initiator Optional

A string. The origin where the request was initiated. This does not change through redirects. The string 'null' is used if this is an opaque origin.

method

A string. A standard HTTP method.

parentDocumentId Optional

A string. The unique identifier for the frame's parent document, if this request is for a frame and has a parent.

parentFrameId

A number. The ID of the frame that wraps the frame which sent the request. Set to -1 if there is no parent frame.

requestId

A string. The ID of the request. Request IDs are unique within a browser session.

tabId

A number. The ID of the tab in which the request takes place. Set to -1 if the request is not related to a tab.

type

ResourceType. The resource type of the request.

url

A string. The URL of the request.

rule

MatchedRule. Details of a matched rule.