I'm seeing a problem with custom Installer plugins on macOS 27 beta 5 and beta 6. I have a .pkg containing a custom Installer plugin. The plugin is properly signed, and if I check it manually from Terminal, codesign is happy with it and doesn't report any errors. However, when I install the package by double-clicking the .pkg in Finder, the plugin is not loaded. I see this in the logs: amfid: /private/tmp/com.apple.installer.../KLNagentInstallPlugin.bundle/Contents/MacOS/KLNagentInstallPlugin not valid: Error Domain=AppleMobileFileIntegrityError Code=-420 "The signature on the file is invalid" So apparently the plugin fails signature validation after Installer extracts it into /private/tmp, even though the same plugin passes codesign validation. This package/plugin worked on earlier macOS versions. So far, I've reproduced the issue on macOS 27 beta 5 and beta 6. Has anyone else run into this? Did anything change in macOS 27 regarding signing or validation of custom Installer plugins? I've also filed this via Feedback Assistant - FB24415432.