api-ms-win-core-winrt-l1-1-0.dll
This file is not a system component: windows itself, not a download. Restore it from the source that installed it rather than downloading a replacement.
Do not download this DLL on its own
Searching for a missing DLL by name leads to sites that hand you that single file. It is one of the oldest and most effective malware delivery methods there is, and a system DLL from an unknown source is indistinguishable from a deliberately modified one. There is never a legitimate reason to obtain a runtime component that way.
What it is
One of the Windows API sets, a family of small forwarding libraries that map API names onto the real implementations. They are part of the operating system and are never distributed separately.
Where you see it: Applications using modern Windows Runtime features on installations with damaged or outdated system files.
Every file starting with api-ms-win- belongs to Windows. Run Windows Update, then "sfc /scannow" and DISM. The one exception is the api-ms-win-crt- family, which the Visual C++ redistributable can supply on older systems.
Why there is nothing to download here
There is no verified download we can offer for this one, because installing a file is not the fix. The steps above are what actually resolves it. That distinction matters: the sites ranking for this file name are selling a download that would not have helped even if it were safe.