Each of these apps had departed the App Store years ago, citing various reasons, but chief among them the limitations of the Mac App Sandbox, which restricts the functionality of apps in the Mac App Store.
I was curious whether Apple made any specific concessions to these developers, and whether those concessions would be opened up to “the rest of us” or not.
Today, Panic launched Transmit 5 on the Mac App Store. It’s a free download, and costs $24.99/year after an initial 7-day free trial.
I downloaded Transmit even though I own a copy of the direct-purchase version. I wanted an answer to my question, which I got, at least partially, by dumping the application binary’s “entitlements”, which represent the sandboxing exceptions that the app has received.
New to me among the entitlements is “com.apple.developer.security.privileged-file-operations”, which is a boolean value set to true for Transmit. I don’t see any Google results for this key, so I’m assuming it’s something new that was added for Panic (and maybe BBEdit), and which may or may not be documented in the future for use by other developers.
Another interesting entitlement is “com.apple.security.automation.apple-events”, which is documented by Apple, but only in the context of the new “Hardened Runtime.” This technology is aimed primarily at developers who are not developing for the Mac App Store, but who want to provide enhanced security for their customers. In that context, I believe this entitlement provides unfettered access to sending AppleEvents, excepting that in Mojave and later the app is still subject to fine-grained system alerts that require user approval for each application that is targeted.
In short: it appears that Transmit possesses at least two “official” entitlements that could be made available, or are perhaps already available, to other developers. One way to find out: add them to your app and submit it for approval!
Update: Thanks to Jeff Nadeau for alerting me to the pertinent API that correlates with the privileged file operations entitlement. NSWorkspaceAuthorization can be used to request privileged file access from the user, and Apple includes a link for requesting access to the entitlement.
Update 2: It turns out my intrigue around “com.apple.security.automation.apple-events” was ill-founded. I assumed that a sandboxed app could use this entitlement to gain unfettered access to automating other apps, but in the case of a sandboxed app it turns out to work in conjunction with the existing “com.apple.security.temporary-exception.apple-events” entitlement, which requires enumeration of specific targets. Thanks to Jeff Johnson and Paolo Andrade for talking me through my misunderstanding of the situation.