[epiphany/pgriffis/web-extension-fixes-2] WebExtensions: Update README with more details

[Patrick Griffis <pgriffis src gnome org>]

commit e33cf991dd45ea873f7461f10e58d953ca4f3475
Author: Patrick Griffis <pgriffis igalia com>
Date:   Thu May 19 11:12:57 2022 -0500

    WebExtensions: Update README with more details

 src/webextension/README.md | 86 ++++++++++++++++++++++++++--------------------
 1 file changed, 48 insertions(+), 38 deletions(-)
---
diff --git a/src/webextension/README.md b/src/webextension/README.md
index 780b87374..74dae0964 100644
--- a/src/webextension/README.md
+++ b/src/webextension/README.md
@@ -1,59 +1,69 @@
-https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API
+# Epiphany WebExtensions
 
-https://github.com/mdn/webextensions-examples
+This is an experimental implementation of 
[WebExtensions](https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API).
 
+Some examples to run can be found here: https://github.com/mdn/webextensions-examples
 
-# Working extensions
 
-- Borderify
-- Apply CSS
-- Page to extension messaging
+It is a work in progress and should be assumed insecure, incomplete, and full of issues for now.
 
-# QUESTIONS
- - Should we use **self** as current module parameter name for consistency or name it like module?
- - Clear definition if get/set functions should be used instead of direct struct access
- - Enfore g_auto free functions implementation?
- - Alignment in header files
- - Should every function of a file has a certain prefix or only non static functions?
- - EphyWebExtensionManager as a singleton?
- 
-# PLAN
+You can track issues here: https://gitlab.gnome.org/GNOME/epiphany/-/issues?label_name[]=5.+WebExtensions
 
-## First release
-Feature set:
- - Un/Load/Enable/Disable xpi and extracted extensions
- - Works for existing and new views
- - Manifest file:
+## Feature Set
+
+- Un/Load/Enable/Disable xpi and extracted extensions
+- Works for existing and new views
+- Manifest file:
     - initial content_scripts
     - initial background page
     - initial background scripts
- - API:
+- WebExtension API:
+    - i18n:
+        - getMessage
+        - getUILanguage
+    - runtime:
+        - sendMessage
+        - onMessage.addListener
     - notifications:
         - create
-    - pageaction:
+    - pageAction:
         - setIcon
         - setTitle
         - show
-        - getTitle
+    - getTitle
     - tabs:
         - insertCSS
         - removeCSS
         - initial query
 
- - Test extensions:
-    - apply-css
-    - borderify
-    
-## Second release
-Feature set:
- - API:
-    - i18n:
-        - getMessage
-        - getUILanguage
-    - runtime:
-        - sendMessage
-        - onMessage.addListener
+### Tested extensions
+
+- apply-css
+- borderify
+- notify-link-clicks-i18n
+
+## Overview
+
+### Contexts
+
+There are roughly 3 contexts in which WebExtension code executes in that need to be handled properly:
+
+#### Content Scripts
+
+The full details can be found here: 
https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/Content_scripts
+
+These run inside of the main web views context and have access to the DOM however they are in
+a private ScriptWorld and cannot directly interact with other extensions or the websites JavaScript.
+
+They also only have access to a small subset of the WebExtensions API.
+
+#### Action Views
+
+These are WebExtension views created when the user triggers an action. They are short lived and limited in 
presentation but have
+full access to the WebExtension APIs.
+
+Since they are isolated from the website they run their scripts in its default context.
 
- - Test extensions:
-    - notify-link-clicks-i18n
+#### Background Page
 
+This is similar to an Action view except that is a long-lived view, Action Views can't get direct access 
with it, and Content Scripts can communicate with it.