src/vs/workbench/api/common/extHostWorkspace.ts/ExtHostWorkspace/workspaceFile
class ExtHostWorkspace:	get workspaceFile(): vscode.Uri | undefined {
		if (this._actualWorkspace) {
			if (this._actualWorkspace.configuration) {
				if (this._actualWorkspace.isUntitled) {
					return URI.from({ scheme: Schemas.untitled, path: basename(dirname(this._actualWorkspace.configuration)) }); // Untitled Workspace: return untitled URI
				}

				return this._actualWorkspace.configuration; // Workspace: return the configuration location
			}
		}

		return undefined;
	}