--- a/devtools/client/framework/target-from-url.js
+++ b/devtools/client/framework/target-from-url.js
@@ -43,17 +43,17 @@ exports.targetFromURL = async function t
 
   const params = url.searchParams;
   const type = params.get("type");
   if (!type) {
     throw new Error("targetFromURL, missing type parameter");
   }
   let id = params.get("id");
   // Allows to spawn a chrome enabled target for any context
-  // (handy to debug chrome stuff in a child process)
+  // (handy to debug chrome stuff in a content process)
   let chrome = params.has("chrome");
 
   let form, isBrowsingContext;
   if (type === "tab") {
     // Fetch target for a remote tab
     id = parseInt(id, 10);
     if (isNaN(id)) {
       throw new Error(`targetFromURL, wrong tab id '${id}', should be a number`);
@@ -74,17 +74,17 @@ exports.targetFromURL = async function t
       id = parseInt(id, 10);
       if (isNaN(id)) {
         id = 0;
       }
       const response = await client.getProcess(id);
       form = response.form;
       chrome = true;
       if (id != 0) {
-        // Child processes are not exposing browsing context target actors with the full
+        // Content processes are not exposing browsing context target actors with the full
         // set of tab-scoped actors we would get from a browser tab. Instead, they only
         // support debugger and console.
         isBrowsingContext = false;
       }
     } catch (ex) {
       if (ex.error == "noProcess") {
         throw new Error(`targetFromURL, process with id '${id}' doesn't exist`);
       }

--- a/devtools/docs/backend/actor-hierarchy.md
+++ b/devtools/docs/backend/actor-hierarchy.md
@@ -68,36 +68,37 @@ RootActor (root.js)
    |       Returned by "connect" on FrameTargetActorProxy.
    |
    |-- WorkerTargetActor (worker.js)
    |   Targets a worker (applies to various kinds like web worker, service
    |   worker, etc.).
    |   Returned by "listWorkers" request to the root actor to get all workers.
    |   Returned by "listWorkers" request to a FrameTargetActorProxy to get
    |   workers for a specific frame.
-   |   Returned by "listWorkers" request to a ChildProcessActor to get workers
-   |   for the chrome of the child process.
+   |   Returned by "listWorkers" request to a ContentProcessTargetActor to get
+   |   workers for the chrome of the child process.
    |
    |-- ChromeWindowTargetActor (chrome-window.js)
    |   Targets a single window, such as a browser window in Firefox, but it can
    |   be used to reach any window in the parent process.
    |   Extends the abstract class BrowsingContextTargetActor.
    |   Returned by "getWindow" request to the root actor.
    |
    |-- ParentProcessTargetActor (parent-process.js)
    |   Targets all resources in the parent process of Firefox (chrome documents,
    |   JSMs, JS XPCOM, etc.).
    |   Extends the abstract class BrowsingContextTargetActor.
    |   Extended by WebExtensionChildActor.
    |   Returned by "getProcess" request without any argument.
    |
-   |-- ChildProcessActor (child-process.js)
-   |   Targets the chrome of the child process (e10s).
-   |   Returned by "getProcess" request with a id argument,
-   |   matching the targeted process.
+   |-- ContentProcessTargetActor (content-process.js)
+   |   Targets all resources in a content process of Firefox (chrome sandboxes,
+   |   frame scripts, documents, etc.)
+   |   Returned by "getProcess" request with a id argument, matching the
+   |   targeted process.
    |
    \-- BrowserAddonActor (addon.js)
        Targets the javascript of add-ons.
        Returned by "listAddons" request.
 ```
 
 ## Target Actors
 

--- a/devtools/server/actors/moz.build
+++ b/devtools/server/actors/moz.build
@@ -24,17 +24,16 @@ DevToolsModules(
     'addon.js',
     'addons.js',
     'animation-type-longhand.js',
     'animation.js',
     'array-buffer.js',
     'breakpoint.js',
     'call-watcher.js',
     'canvas.js',
-    'child-process.js',
     'common.js',
     'css-properties.js',
     'csscoverage.js',
     'device.js',
     'emulation.js',
     'environment.js',
     'errordocs.js',
     'frame.js',

--- a/devtools/server/actors/root.js
+++ b/devtools/server/actors/root.js
@@ -514,17 +514,18 @@ RootActor.prototype = {
     if ((!("id" in request)) || request.id === 0) {
       if (this._parentProcessTargetActor && (!this._parentProcessTargetActor.docShell ||
           this._parentProcessTargetActor.docShell.isBeingDestroyed)) {
         this._globalActorPool.removeActor(this._parentProcessTargetActor);
         this._parentProcessTargetActor = null;
       }
       if (!this._parentProcessTargetActor) {
         // Create a ParentProcessTargetActor for the parent process
-        const { ParentProcessTargetActor } = require("devtools/server/actors/targets/parent-process");
+        const { ParentProcessTargetActor } =
+          require("devtools/server/actors/targets/parent-process");
         this._parentProcessTargetActor = new ParentProcessTargetActor(this.conn);
         this._globalActorPool.addActor(this._parentProcessTargetActor);
       }
 
       return { form: this._parentProcessTargetActor.form() };
     }
 
     const { id } = request;

rename from devtools/server/actors/child-process.js
rename to devtools/server/actors/targets/content-process.js
--- a/devtools/server/actors/child-process.js
+++ b/devtools/server/actors/targets/content-process.js
@@ -1,27 +1,34 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 "use strict";
 
+/*
+ * Target actor for all resources in a content process of Firefox (chrome sandboxes, frame
+ * scripts, documents, etc.)
+ *
+ * See devtools/docs/backend/actor-hierarchy.md for more details.
+ */
+
 const { Cc, Ci, Cu } = require("chrome");
 const Services = require("Services");
 
 const { ChromeDebuggerActor } = require("devtools/server/actors/thread");
 const { WebConsoleActor } = require("devtools/server/actors/webconsole");
 const makeDebugger = require("devtools/server/actors/utils/make-debugger");
 const { ActorPool } = require("devtools/server/main");
 const { assert } = require("devtools/shared/DevToolsUtils");
-const { TabSources } = require("./utils/TabSources");
+const { TabSources } = require("devtools/server/actors/utils/TabSources");
 
 loader.lazyRequireGetter(this, "WorkerTargetActorList", "devtools/server/actors/worker/worker-list", true);
 
-function ChildProcessActor(connection) {
+function ContentProcessTargetActor(connection) {
   this.conn = connection;
   this._contextPool = new ActorPool(this.conn);
   this.conn.addActorPool(this._contextPool);
   this.threadActor = null;
 
   // Use a see-everything debugger
   this.makeDebugger = makeDebugger.bind(null, {
     findDebuggees: dbg => dbg.findAllGlobals(),
@@ -30,20 +37,20 @@ function ChildProcessActor(connection) {
 
   const sandboxPrototype = {
     get tabs() {
       const tabs = [];
       const windowEnumerator = Services.ww.getWindowEnumerator();
       while (windowEnumerator.hasMoreElements()) {
         const window = windowEnumerator.getNext().QueryInterface(Ci.nsIDOMWindow);
         const tabChildGlobal = window.QueryInterface(Ci.nsIInterfaceRequestor)
-                                   .getInterface(Ci.nsIDocShell)
-                                   .sameTypeRootTreeItem
-                                   .QueryInterface(Ci.nsIInterfaceRequestor)
-                                   .getInterface(Ci.nsIContentFrameMessageManager);
+                                     .getInterface(Ci.nsIDocShell)
+                                     .sameTypeRootTreeItem
+                                     .QueryInterface(Ci.nsIInterfaceRequestor)
+                                     .getInterface(Ci.nsIContentFrameMessageManager);
         tabs.push(tabChildGlobal);
       }
       return tabs;
     },
   };
 
   // Scope into which the webconsole executes:
   // A sandbox with chrome privileges with a `tabs` getter.
@@ -53,20 +60,20 @@ function ChildProcessActor(connection) {
     sandboxPrototype,
   });
   this._consoleScope = sandbox;
 
   this._workerList = null;
   this._workerTargetActorPool = null;
   this._onWorkerListChanged = this._onWorkerListChanged.bind(this);
 }
-exports.ChildProcessActor = ChildProcessActor;
+exports.ContentProcessTargetActor = ContentProcessTargetActor;
 
-ChildProcessActor.prototype = {
-  actorPrefix: "process",
+ContentProcessTargetActor.prototype = {
+  actorPrefix: "contentProcessTarget",
 
   get isRootActor() {
     return true;
   },
 
   get exited() {
     return !this._contextPool;
   },
@@ -155,11 +162,11 @@ ChildProcessActor.prototype = {
     // window mediator doesn't work in child.
     // it doesn't throw, but doesn't return any window
   },
 
   postNest: function() {
   },
 };
 
-ChildProcessActor.prototype.requestTypes = {
-  "listWorkers": ChildProcessActor.prototype.onListWorkers,
+ContentProcessTargetActor.prototype.requestTypes = {
+  "listWorkers": ContentProcessTargetActor.prototype.onListWorkers,
 };

--- a/devtools/server/actors/targets/moz.build
+++ b/devtools/server/actors/targets/moz.build
@@ -2,13 +2,14 @@
 # vim: set filetype=python:
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 DevToolsModules(
     'browsing-context.js',
     'chrome-window.js',
+    'content-process.js',
     'frame-proxy.js',
     'frame.js',
     'parent-process.js',
     'worker.js',
 )

--- a/devtools/server/performance/memory.js
+++ b/devtools/server/performance/memory.js
@@ -10,18 +10,17 @@ const { expectState } = require("devtool
 
 loader.lazyRequireGetter(this, "EventEmitter", "devtools/shared/event-emitter");
 loader.lazyRequireGetter(this, "DeferredTask",
   "resource://gre/modules/DeferredTask.jsm", true);
 loader.lazyRequireGetter(this, "StackFrameCache",
   "devtools/server/actors/utils/stack", true);
 loader.lazyRequireGetter(this, "ChromeUtils");
 loader.lazyRequireGetter(this, "ParentProcessTargetActor", "devtools/server/actors/targets/parent-process", true);
-loader.lazyRequireGetter(this, "ChildProcessActor",
-                         "devtools/server/actors/child-process", true);
+loader.lazyRequireGetter(this, "ContentProcessTargetActor", "devtools/server/actors/targets/content-process", true);
 
 /**
  * A class that returns memory data for a parent actor's window.
  * Using a tab-scoped actor with this instance will measure the memory footprint of its
  * parent tab. Using a global-scoped actor instance however, will measure the memory
  * footprint of the chrome window referenced by its root actor.
  *
  * To be consumed by actor's, like MemoryActor using this module to
@@ -139,17 +138,17 @@ Memory.prototype = {
    *
    * @returns {String} The snapshot id.
    */
   saveHeapSnapshot: expectState("attached", function(boundaries = null) {
     // If we are observing the whole process, then scope the snapshot
     // accordingly. Otherwise, use the debugger's debuggees.
     if (!boundaries) {
       if (this.parent instanceof ParentProcessTargetActor ||
-          this.parent instanceof ChildProcessActor) {
+          this.parent instanceof ContentProcessTargetActor) {
         boundaries = { runtime: true };
       } else {
         boundaries = { debugger: this.dbg };
       }
     }
     return ChromeUtils.saveHeapSnapshotGetId(boundaries);
   }, "saveHeapSnapshot"),
 

--- a/devtools/server/startup/content-process.jsm
+++ b/devtools/server/startup/content-process.jsm
@@ -71,20 +71,20 @@ function init(msg) {
     const loader = setupServer(mm);
 
     // Connect both parent/child processes debugger servers RDP via message
     // managers
     const { DebuggerServer } = loader.require("devtools/server/main");
     const conn = DebuggerServer.connectToParent(prefix, mm);
     conn.parentMessageManager = mm;
 
-    const { ChildProcessActor } =
-        loader.require("devtools/server/actors/child-process");
+    const { ContentProcessTargetActor } =
+        loader.require("devtools/server/actors/targets/content-process");
     const { ActorPool } = loader.require("devtools/server/main");
-    const actor = new ChildProcessActor(conn);
+    const actor = new ContentProcessTargetActor(conn);
     const actorPool = new ActorPool(conn);
     actorPool.addActor(actor);
     conn.addActorPool(actorPool);
 
     const response = { actor: actor.form() };
     mm.sendAsyncMessage("debug:content-process-actor", response);
   });
 }

--- a/devtools/server/tests/unit/test_MemoryActor_saveHeapSnapshot_03.js
+++ b/devtools/server/tests/unit/test_MemoryActor_saveHeapSnapshot_03.js
@@ -1,15 +1,15 @@
 /* Any copyright is dedicated to the Public Domain.
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
 
 // Test that we can save full runtime heap snapshots when attached to the
-// ParentProcessTargetActor or a ChildProcessActor.
+// ParentProcessTargetActor or a ContentProcessTargetActor.
 
 const { OS } = require("resource://gre/modules/osfile.jsm");
 
 const run_test = makeFullRuntimeMemoryActorTest(async function(client, memoryFront) {
   const snapshotFilePath = await memoryFront.saveHeapSnapshot();
   ok(!!(await OS.File.stat(snapshotFilePath)),
      "Should have the heap snapshot file");
   const snapshot = ChromeUtils.readHeapSnapshot(snapshotFilePath);

--- a/devtools/shared/client/debugger-client.js
+++ b/devtools/shared/client/debugger-client.js
@@ -509,18 +509,18 @@ DebuggerClient.prototype = {
         this.registerClient(traceClient);
       }
       onResponse(response, traceClient);
       return [response, traceClient];
     });
   },
 
   /**
-   * Fetch the ParentProcessTargetActor for the main process or ChildProcessActor for a
-   * a given child process ID.
+   * Fetch the ParentProcessTargetActor for the main process or
+   * ContentProcessTargetActor for a given content process ID.
    *
    * @param number id
    *        The ID for the process to attach (returned by `listProcesses`).
    *        Connected to the main process if omitted, or is 0.
    */
   getProcess: function(id) {
     const packet = {
       to: "root",

--- a/devtools/shared/client/root-client.js
+++ b/devtools/shared/client/root-client.js
@@ -86,18 +86,18 @@ RootClient.prototype = {
    * List the running processes.
    *
    * @param function onResponse
    *        Called with the response packet.
    */
   listProcesses: DebuggerClient.requester({ type: "listProcesses" }),
 
   /**
-   * Retrieve all service worker registrations as well as workers from the parent
-   * and child processes. Listing service workers involves merging information coming from
+   * Retrieve all service worker registrations as well as workers from the parent and
+   * content processes. Listing service workers involves merging information coming from
    * registrations and workers, this method will combine this information to present a
    * unified array of serviceWorkers. If you are only interested in other workers, use
    * listWorkers.
    *
    * @return {Object}
    *         - {Array} service
    *           array of form-like objects for serviceworkers
    *         - {Array} shared