installing safari extension single file

Hey gerald bc,

Let's try the following steps below:

Use Safari extensions on your Mac

Install extensions

Start by installing the latest macOS updates to make sure that Safari is up to date. You need Safari 12 or later to get Safari extensions from the App Store.

Find and install an extension

1. Open Safari and choose Safari > Safari Extensions from the menu bar.

2. The App Store opens to the Safari Extensions page. To download and install an extension, click Get or click the price. You might be asked to sign in with your Apple ID.

3. Click Install.

4. After the extension is installed, click Open and follow the onscreen instructions provided by the extension.

If the issue persists, let us know the exact error you receive and we'll search for other relevant steps.

Cheers