diff --git a/devtools/server/actors/targets/window-global.js b/devtools/server/actors/targets/window-global.js
index e9972ab45d11..d3d42a8e5cad 100644
--- a/devtools/server/actors/targets/window-global.js
+++ b/devtools/server/actors/targets/window-global.js
@@ -141,13 +141,8 @@ const windowGlobalTargetPrototype = {
    *
    * ### Main requests:
    *
-   * `attach`/`detach` requests:
-   *  - start/stop document watching:
-   *    Starts watching for new documents and emits `tabNavigated` and
-   *    `frameUpdate` over RDP.
-   *  - retrieve the thread actor:
-   *    Instantiates a ThreadActor that can be later attached to in order to
-   *    debug JS sources in the document.
+   * `detach`:
+   *  Stop document watching and cleanup everything that the target and its children actors created.
    * `switchToFrame`:
    *  Change the targeted document of the whole actor, and its child target-scoped actors
    *  to an iframe or back to its original document.
@@ -1152,18 +1147,6 @@ const windowGlobalTargetPrototype = {
 
   // Protocol Request Handlers
 
-  attach(request) {
-    if (this.isDestroyed()) {
-      throw {
-        error: "destroyed",
-      };
-    }
-
-    return {
-      threadActor: this.threadActor.actorID,
-    };
-  },
-
   detach(request) {
     if (!this._detach()) {
       throw {
diff --git a/devtools/server/tests/xpcshell/testactors.js b/devtools/server/tests/xpcshell/testactors.js
index cf6df1c3440d..2d9f4abdd25c 100644
--- a/devtools/server/tests/xpcshell/testactors.js
+++ b/devtools/server/tests/xpcshell/testactors.js
@@ -154,7 +154,6 @@ const TestTargetActor = protocol.ActorClassWithSpec(windowGlobalTargetSpec, {
     this._global.wrappedJSObject = global;
     this.threadActor = new ThreadActor(this, this._global);
     this.conn.addActor(this.threadActor);
-    this._attached = false;
     this._extraActors = {};
     // This is a hack in order to enable threadActor to be accessed from getFront
     this._extraActors.threadActor = this.threadActor;
@@ -210,16 +209,7 @@ const TestTargetActor = protocol.ActorClassWithSpec(windowGlobalTargetSpec, {
     return { ...response, ...actors };
   },
 
-  attach: function(request) {
-    this._attached = true;
-
-    return { threadActor: this.threadActor.actorID };
-  },
-
   detach: function(request) {
-    if (!this._attached) {
-      return { error: "wrongState" };
-    }
     this.threadActor.destroy();
     return { type: "detached" };
   },