Open folder feature for all items within the solution explorer.
Download this extension from the Visual Studio Marketplace
The folder can be opened in the fllowing application:
Open the containing folder of a file in the Solution Explorer
Select a file or a project in the Solution Explorer and right-click it.
And then select the "Open folder" to open the explorer.
Open output folder of a project from solution explorer
Select a project in the Solution Explorer and right-click it.
And then select the "Open output path" to open the explorer.