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+# Course Cache
+
+(iykyk)
+
+
+This guide explains how to install a browser extension directly from its source directory for development and testing.
+
+This process is commonly referred to as **loading an unpacked extension**.
+
+> [!WARNING]
+> Only load unpacked extensions from code you trust. Development extensions bypass the normal browser extension-store installation process and may request powerful browser permissions. Chrome specifically recommends using unpacked extensions only for trusted code during development.
+
+## Supported Browsers
+
+The process is similar across most desktop Chromium-based browsers, including:
+
+* Google Chrome
+* Microsoft Edge
+* Brave
+* Opera
+* Other Chromium-based browsers that expose the standard extensions management page
+
+The examples below focus on desktop browsers.
+
+---
+
+Chrome and Edge both load development extensions by selecting the directory containing the extension's source files and manifest.
+
+If you downloaded the extension as a ZIP file, extract it first.
+
+For example:
+
+```text
+Downloads/
+└── nccache/
+    ├── src/
+    └── ...
+```
+
+Do **not** select the ZIP file itself when using **Load unpacked**.
+
+---
+
+# Google Chrome
+
+## 1. Open the Extensions Page
+
+Enter the following into Chrome's address bar:
+
+```text
+chrome://extensions
+```
+
+Chrome also exposes the extensions manager through its Extensions menu.
+
+## 2. Enable Developer Mode
+
+Turn on:
+
+```text
+Developer mode
+```
+
+The toggle is normally located near the top of the Extensions page.
+
+## 3. Load the Extension
+
+Click:
+
+```text
+Load unpacked
+```
+
+Then select the directory containing:
+
+```text
+manifest.json
+```
+
+For example:
+
+```text
+~/Downloads/ncache/src/
+```
+
+Chrome will install the extension directly from that directory.
+
+## 4. Verify the Extension
+
+The extension should now appear on the Extensions page.
+
+Depending on the extension, you may also see its icon in Chrome's Extensions menu.
+
+You can pin it to the toolbar from the Extensions menu if needed.
+
+---
+
+# Microsoft Edge
+
+## 1. Open the Extensions Page
+
+Open:
+
+```text
+edge://extensions
+```
+
+Alternatively, use:
+
+```text
+Settings and more
+→ Extensions
+→ Manage extensions
+```
+
+Microsoft documents the same developer-mode sideloading workflow for Edge.
+
+## 2. Enable Developer Mode
+
+Turn on:
+
+```text
+Developer mode
+```
+
+## 3. Load the Extension
+
+Click:
+
+```text
+Load unpacked
+```
+
+Select the directory containing the extension source files and:
+
+```text
+manifest.json
+```
+
+Microsoft Edge will load the extension for local testing.
+
+---
+
+# Brave
+
+Open Brave and navigate to:
+
+```text
+Menu
+→ More tools
+→ Extensions
+```
+
+Brave exposes installed extension management through this page.
+
+From the extensions page:
+
+1. Enable **Developer mode**.
+2. Click **Load unpacked**.
+3. Select your extension directory.
+4. Confirm that the extension appears in the installed extensions list.
+
+The directory should be the folder containing:
+
+```text
+manifest.json
+```
+
+---
+
+# Opera
+
+## 1. Open the Extensions Page
+
+Enter:
+
+```text
+opera://extensions/
+```
+
+Opera documentation also refers to this page as:
+
+```text
+opera:extensions
+```
+
+## 2. Enable Developer Mode
+
+Enable:
+
+```text
+Developer Mode
+```
+
+## 3. Load the Extension
+
+Choose:
+
+```text
+Load unpacked
+```
+
+or the equivalent **Load Extension** option shown by your Opera version.
+
+Select the extension directory containing the manifest and other source files. Opera documents loading extensions directly from their directories for development and testing.
+
+---
+
+# Updating the Extension During Development
+
+Loading an unpacked extension does **not** mean you have to reinstall it every time you change your code.
+
+Edit your source normally:
+
+```text
+my-extension/
+├── manifest.json
+├── background.js
+└── content.js
+```
+
+For example:
+
+```bash
+code my-extension/
+```
+
+After making changes, return to the browser's Extensions page.
+
+Find your extension and click its:
+
+```text
+Reload
+```
+
+button or reload icon.
+
+Chrome and Opera both expose a reload mechanism specifically for updating development extensions after source changes.
+
+A typical workflow is therefore:
+
+```text
+Edit code
+   ↓
+Save files
+   ↓
+Open Extensions page
+   ↓
+Reload extension
+   ↓
+Refresh the webpage being tested
+   ↓
+Test changes
+```
+
+You may need to refresh any existing webpage where your extension's content scripts are running.
+
+---
+
+# Inspecting and Debugging the Extension
+
+Development extensions can be debugged using the browser's Developer Tools.
+
+## Popup
+
+If the extension has a popup:
+
+1. Open the extension popup.
+2. Right-click inside it.
+3. Choose **Inspect** or **Inspect element**.
+
+This opens a dedicated DevTools window for the popup.
+
+Opera, for example, explicitly supports inspecting extension popups through its developer tools.
+
+## Web Page / Content Scripts
+
+For code injected into a webpage:
+
+```text
+Right-click webpage
+→ Inspect
+```
+
+Use the normal DevTools:
+
+```text
+Console
+Sources
+Network
+Elements
+```
+
+to diagnose the extension.
+
+## Background / Service Worker
+
+For extensions using a background service worker, the Extensions page usually exposes an inspection link for the worker.
+
+Look around the extension's development information for something similar to:
+
+```text
+Service worker
+```
+
+and select its inspection link.
+
+---
+
+# Common Problems
+
+## "Manifest file is missing or unreadable"
+
+Make sure you selected the correct directory.
+
+Incorrect:
+
+```text
+my-extension/
+└── extension/
+    ├── manifest.json
+    └── content.js
+```
+
+while selecting:
+
+```text
+my-extension/
+```
+
+Correct:
+
+```text
+my-extension/
+└── extension/
+    ├── manifest.json
+    └── content.js
+        ↑
+        select this directory
+```
+
+The folder selected through **Load unpacked** should directly contain:
+
+```text
+manifest.json
+```
+
+---
+
+## Extension Does Not Appear to Update
+
+After changing the code:
+
+1. Save your files.
+2. Open the Extensions page.
+3. Click **Reload** on the extension.
+4. Refresh the webpage you are testing.
+
+For Chrome:
+
+```text
+chrome://extensions
+```
+
+For Edge:
+
+```text
+edge://extensions
+```
+
+For Opera:
+
+```text
+opera://extensions/
+```
+
+---
+
+## Extension Shows an Error
+
+Open the Extensions page and inspect the error associated with the extension.
+
+Common causes include:
+
+```text
+Invalid manifest.json
+Missing files
+Invalid permissions
+JavaScript syntax errors
+Incorrect file paths
+Unsupported extension APIs
+```
+
+Start by validating that `manifest.json` contains valid JSON.
+
+For example:
+
+```json
+{
+  "manifest_version": 3,
+  "name": "My Development Extension",
+  "version": "1.0.0"
+}
+```
+
+---
+
+## Changes to Content Scripts Are Not Visible
+
+Reloading the extension does not necessarily update code that was already injected into an existing page.
+
+Use:
+
+```text
+Reload extension
+→ Refresh target webpage
+```
+
+If you're debugging several tabs, refresh each affected tab.
+
+---
+
+# Removing the Development Extension
+
+Open your browser's Extensions page:
+
+```text
+Chrome:  chrome://extensions
+Edge:    edge://extensions
+Opera:   opera://extensions/
+```
+
+Locate the development extension and choose:
+
+```text
+Remove
+```
+
+or:
+
+```text
+Uninstall
+```
+
+Removing the extension from the browser does **not** delete your local source directory.
+
+---
+
+# Quick Reference
+
+| Browser | Extensions Page                | Installation                   |
+| ------- | ------------------------------ | ------------------------------ |
+| Chrome  | `chrome://extensions`          | Developer mode → Load unpacked |
+| Edge    | `edge://extensions`            | Developer mode → Load unpacked |
+| Brave   | Extensions / Manage Extensions | Developer mode → Load unpacked |
+| Opera   | `opera://extensions/`          | Developer Mode → Load unpacked |
+
+The general Chromium development workflow is:
+
+```text
+1. Obtain or build the extension source
+2. Extract it if necessary
+3. Confirm manifest.json exists
+4. Open the browser's Extensions page
+5. Enable Developer mode
+6. Click Load unpacked
+7. Select the extension directory
+8. Test the extension
+9. Reload it after source changes
+```
+
+---
+
+# Security Notes
+
+Development extensions should be treated similarly to locally running applications.
+
+Before loading an unfamiliar extension:
+
+* Review its `manifest.json`.
+* Check requested permissions.
+* Review background/service-worker scripts.
+* Review content scripts.
+* Check for unexpected network requests.
+* Avoid loading extension code from unknown or untrusted sources.
+
+In particular, pay attention to permissions such as:
+
+```json
+{
+  "permissions": [
+    "tabs",
+    "cookies",
+    "storage"
+  ],
+  "host_permissions": [
+    "<all_urls>"
+  ]
+}
+```
+
+An extension with broad permissions may be able to interact with a significant amount of browser activity.
+
+For normal development and testing, prefer loading the extension directly from a local source directory rather than installing unknown prebuilt packages.