Which plist contains information regarding allowed system extensions?

The correct answer is that the plist containing information about allowed system extensions is located at /Library/SystemExtensions/db.plist. This plist file is specifically designed to manage system extensions on macOS. System extensions are a way for developers to extend the functionality of the operating system without needing to modify the kernel, which enhances security and stability. The database at this location keeps track of which system extensions have been allowed or are in use, facilitating the management of these components.

The other options include plists located in different directories that do not serve the same purpose. The plist at /var/db/SystemExtensions.plist is less relevant as it does not specifically track allowed systems extensions but might contain other system information. The plist located at /System/Library/Extensions.plist pertains to kernel extensions, which are a different category that influences how the operating system interacts with hardware. Lastly, /var/db/kexts.plist is focused on kernel extensions as well and is not concerned with system extensions. Each of these alternatives lacks the specific focus required to track allowed system extensions as effectively as the designated db.plist in the discussed location does.