Traditionally, TFS only supported server workspaces. Local workspaces were rolled out in TFS 2012. A local workspace allows you to work disconnected from the server. All core version control operations can be performed without any server connectivity. Local workspaces listen for changes on the filesystem to infer the operations being performed. For example, a new file created in the workspace directly from the filesystem will show up as a pending change. Users who used Subversion source control will be familiar with local workspaces. Read more about the workings of local workspaces at https://msdn.microsoft.com/en-us/library/bb892960.aspx.
Many tools and extensions that work in concert with Visual Studio generate temporary files within the local workspace directories. For example, ReSharper, a developer productivity extension for Visual Studio, generates _Resharper.[SolutionName]
files that are (by default) included in pending...