Unable to add entitlement

would like to know this as well.

This is an Apple-only entitlement. I’m not sure why your project is trying to use it, but there is no way to do so.

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Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

RunningBoard has its origins on iOS [1] and was brought to the Mac as an implementation detail of Mac Catalyst [2]. It has neither a direct API nor any ‘user serviceable parts’ [3]

I’m not sure whether RunningBoard assertions are related to your WKWebView media problems — I’m not an expert on WebKit or the media subsystem — but I can guarantee you that you won’t be able to fix them via the com.apple.runningboard.assertions.webkit entitlement. That is, as I mentioned above, an Apple-only thing.

As to what you should do, my advice is that you start a new thread that describes the actual issue you’re having, tagging it appropriately in the hope of attracting attention from folks who are WebKit and media subsystem experts. If that doesn’t pan out, open a DTS tech support incident so that one of my colleagues can help you directly.

Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

[1] The internal name for the Home screen on iOS is SpringBoard, and over the years various ‘board’ subsystems have been split out into their own processes, RunningBoard being one of them.

[2] As to what it does, note that the article you referenced has misinterpreted the term assertion. To quote the runningboardd man page:

runningboardd is a daemon that manages process assertions to ensure those processes are kept in the appropriate state while assertions are in effect.

In this context an assertion is something that a process raises to tell the system about its state. For example, a UIApplication background task asserts that the app must not be suspended. Indeed, I use this terminology in my UIApplication Background Task Notes post. It would be reasonable to assume that RunningBoard forms the back end of that API when you call it from a Mac Catalyst app (although I must admit that I haven’t investigated whether that’s actually the case :-).

[3] To continue quoting that man page:

There are no options for runningboardd, and users should not run runningboardd manually.

I only wish that with so many people complaining, the issue would be proactively addressed or explained by Apple.

If you want help with this, I recommend that you follow my advice from my previous post.

there is still this other entitlement, com.apple.multitasking.systemappassertions, that I'd be interested to know more about.

All I can say definitively here is that this another Apple-only entitlement. Looking at the name it’s seems likely that it’s related to the same assertion subsystem I described above but, given that is private, I can’t go into the details.

Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

After lots of playing around with older entitlement files. I managed to fix it! I also downgraded to 13.2.1

Have same issue, do you fix it?

Yes, it would be super helpful and appreciated to hear how you solved this!

Goto MenuBar and find product

-> Goto Menu menu -> Scheme -> Edit Scheme -> It comes up with popup -> Select "Run" - -> Select "Arguments" -> Then Environment Variables -> after this click on "+" button set "OS_ACTIVITY_MODE = disable"

Having the app running in simulator I've connected to webView via a web inspector. May be that is related.