Could not resolve this, but have re-written the keyboard extension using KeyboardKit, so the link to Github now will no longer show the code I was referring to.

Reporting the same, as per the topic title, Safari Web Inspector on macOS connecting to a WebView in an iOS app built with Cordova immediately crashes the iOS app or if debugging through Xcode freezes with WebThread (11): EXC_BAD_ACCESS (code=1, address=0x11) Using MacBookPro10,1 with macOS 11.3.1 running Xcode 12.5 and Safari 14.1 and iPad 8,11 with iPadOS 14.5.1 JavaScriptCore`invocation function for block in Inspector::RemoteConnectionToTarget::dispatchAsyncOnTarget(WTF::Functionvoid ()&&): 0x1aeeca9f8 +0: ldr x8, [x0, #0x20] 0x1aeeca9fc +4: ldr x0, [x8] 0x1aeecaa00 +8: ldr x1, [x0] 0x1aeecaa04 +12: ldraa x2, [x1, #0x10]! 0x1aeecaa08 +16: movk x1, #0x685c, lsl #48 0x1aeecaa0c +20: braa x2, x1