It's an Azure DevOps (formerly TFS, VSTS) extension with a custom release task for getting files from TFVC source control. The built-in functionality allows one to designate a source control repository as the source of artifacts, but it only supports downloading the whole repository. This task would download just one folder.
Download it from the Visual Studio Marketplace at https://marketplace.visualstudio.com/items?itemName=sevaalekseyev.tfvcget