{% data variables.product.prodname_copilot_extensions %} are **a type of {% data variables.product.prodname_github_app %} that integrates the power of external tools into {% data variables.product.prodname_copilot_chat %}**. {% data variables.product.prodname_copilot_extensions_short %} can be developed by anyone, for private or public use, and can be shared with others through the {% data variables.product.prodname_marketplace %}.