Describe the bug

Several users have reported that the Ruffle extension does not work in Safari 16. The extension popup always says "Checking Ruffle status on current tab..." and the Ruffle player does not appear on the page. Initial investigation by @kmeisthax suggests that there was some change in Safari 16 to how postMessage works, which was not mentioned in the release notes.

Expected behavior

The extension should work as it does in other browsers.

Affected platform

Browser's extension

Operating system

MacOS Monterey, Big Sur, and Ventura

Browser

Safari 16

Additional information

No response