The implementation of is discussed in the developer-focused documentation here(https://radix-engine-docs.radixdlt.com//native/auth/systemmodule.html).
Developer-focused documentation on the design and implementation of the Babylon Radix Engine is available at https://radix-engine-docs.radixdlt.com/(https://radix-engine-docs.radixdlt.com/).
Legacy documentation: Radix Engine