The api-ms-win-crt-heap-l1-1-0.dll is a Dynamic Link Library (DLL) file provided by Microsoft as part of the Windows operating system. It serves as an "ApiSet Stub DLL," which means it's a part of the Windows API set that acts as a sort of forwarding service for function calls. Essentially, when software wants to perform a specific action related to heap management, it calls upon functions within this DLL, and the DLL routes those calls to the appropriate places within the Windows OS. Heap management is a crucial part of computer programming that deals with the allocation and deallocation of memory in the "heap," a region of a computer's storage that is used for dynamically allocated memory.

This DLL file is typically involved in applications built using the Microsoft Visual C++ Redistributable, and it's one of those files that are necessary for the proper functioning of a lot of different software on a Windows computer. If it's missing or corrupted, you might encounter errors related to application performance or even an application's inability to start. In summary, api-ms-win-crt-heap-l1-1-0.dll is an essential system file that plays a key role in facilitating heap memory management calls for various applications running on a Windows system.