> ## Documentation Index > Fetch the complete documentation index at: https://docs.near.org/llms.txt > Use this file to discover all available pages before exploring further. # Runtime > Explore NEAR Protocol's runtime system, including core runtime operations, cross-contract calls, action and data receipts, and state management. This section contains videos that explore the core Runtime, its operation, and how it implements cross-contract calls. ## Runtime Overview An in-depth code overview of NEAR Runtime.