Did you ever figure out a solution to this @gshackney ?

@daniel_ross Looks like you can add the link to the extension in the VPP store now and use the JSS to assign it to computers. I'm going to test this today to see if it prompts people or not. Really only affects Safari 12 and later.

Gabe Shackney
Princeton Public Schools

I am interested in this also. I have been attempting to install an extension called "Classlink". I got as far as deploying it through the MASA tab in JAMF, and it does install. The problem now being it doesn't check the box next to the extension in Safari/Preferences/Extensions so it can be used or even recognized as present. Anyone know how to get this checked?

@gmorgan
Yup, that's as far as I got as well. If you figure that part out please let me know. Im sure you could AppleScript it, but I wouldnt know where to begin in that process with the newer Safari.

Gabe Shackney
Princeton Public Schools

So, I haven't gotten really anywhere, but I wanted to update you on my progress. Maybe my attempts might spark something in another brain? As previously, the app is installed and we just need to "check the box" to enable it. I have created a PPPC config to give Terminal access for the next part (due to Mojave's security issues). I am attempting this script:

...as a policy. It runs the script via the policy but returns an error: "script result: missing value"

To be fair, I absolutely stole that script and modified it because I am terrible at scripting. Any scripting gurus wanna take a shot at it??

So, it turns out based on Apple's SIP, that you can only push out the app/extension, but not enable it. Enabling is a manual process. It says as much on their extension page of the App Store:

Even as the owner of the plist file, you don't have anything more than read access to it. They really have these user preferences locked down.