McAffee and Windows picked up the download file both as an error and a threat to download this on my computer.
Hi North Star.
As this shows the same issue as you sent, I assume you copied the code into a .js file on your computer and tried to execute it.
The script is used with an extension you have to install in your browser first. I use Tampermonkey (https://www.tampermonkey.net/) for this.
Just install Tampermonkey for your browser, click on "Install Script" next to the link in the OP and you are good to go.
If that didn't solve the issue, just write me the steps that led to the image you sent and which browser you are using.