Preparing the file (method 1)

1. Visit Chrome web store and install an extension of your choice
2. Go to chrome://version/ and check the “Profile path”, for example:
   /Users/username/mlx/profiles/46f57e7c-b80a-371e-9a1e-568cb2830359/391670f2-9c19-4279-9a3b-5a9fcc1f1793/065a29da-a68a-4c56-bf33-3d5019abfe60/Default
3. Open this path in your file explorer and go to the Extensions folder, where you will see a folder named with an extension ID
4. Once you open it, you'll see a folder named with an extension version – this is the one that you'll need further (see “Using the file”)

Preparing the file (method 2)

1. Visit Chrome web store
2. Choose an extension and copy its ID from the address bar: 
   https://chromewebstore.google.com/detail/extension-name/extension-id
3. Paste the ID into CRXViewer and select "Download as ZIP"
4. Extract your ZIP file into a new folder

Note that a .crx file won't work on its own. Instead, you need to have a folder with your extension files, including manifest.json. Each extension must have a separate folder.

Using the file

1. Go to the mlx folder in your file system:
   1. Windows: C:\Users\%username%\mlx
   2. macOS: /Users/%username%/mlx
   3. Linux: /home/%username%/mlx
2. Create a new folder called custom_extensions and a folder mimic inside of it
3. Place your extension folder from step 4 above into the mimic folder

Video tutorial

Preparing the file

1. Visit the Firefox browser add-ons page
2. Choose your extension and right-click the "Add to Firefox" button, then choose "Save Link As"
3. An .xpi file will be downloaded to your computer

Using the file

1. Go to the mlx folder in your file system:
   1. Windows: C:\Users\%username%\mlx
   2. macOS: /Users/%username%/mlx
   3. Linux: /home/%username%/mlx
2. Create a new folder called custom_extensions and a folder stealthfox inside of it
3. Place your .xpi file from step 3 above into the stealthfox folder

Video tutorial