Chrome DevTools debugger issue

My Chrome (Windows 10) just updated to:

Version 115.0.5790.110 (Official Build) (64-bit)

And I now get the following message in the console when I open DevTools on an Observable notebook:

DevTools debugger is disabled because it is attached to a process that hosts multiple top-level frames, where DevTools debugger doesn’t work properly. Please relaunch the browser with --disable-features=ProcessPerSiteUpToMainFrameThreshold to enable debugger.

And indeed, I am unable to debug the Observable notebook.

I’ve checked out a few of my Observable notebooks, and they all lead to this message. And I’ve checked a few random non-Observable pages, and they don’t lead to this message. I’ve restarted Chrome, and that didn’t make a difference.

If I run Chrome with the suggested flag:
then I am able to debug as usual. But I’m not sure why I need to do this to debug my Observable notebooks.

Any one else seeing this?

I’m not using Chrome Beta, just the standard release, and I haven’t altered any settings recently that I am aware of.

I think there should be a flag that you can set at chrome://flags/#enable-process-per-site-up-to-main-frame-threshold?

The reason you need to set this flag all of a sudden is likely that the code in an Observable notebook runs in a separate browsing context (different domain) in order to isolate it. I don’t know the details about this flag (and I can’t test since I’m on macOS), but I suspect that this change will affect other platforms like CodePen as well.