src/vs/workbench/contrib/workspaces/browser/workspaces.contribution.ts/WorkspacesFinderContribution/findWorkspaces
class WorkspacesFinderContribution:	private async findWorkspaces(): Promise<void> {
		const folder = this.contextService.getWorkspace().folders[0];
		if (!folder || this.contextService.getWorkbenchState() !== WorkbenchState.FOLDER || isVirtualWorkspace(this.contextService.getWorkspace())) {
			return; // require a single (non virtual) root folder
		}

		const rootFileNames = (await this.fileService.resolve(folder.uri)).children?.map(child => child.name);
		if (Array.isArray(rootFileNames)) {
			const workspaceFiles = rootFileNames.filter(hasWorkspaceFileExtension);
			if (workspaceFiles.length > 0) {
				this.doHandleWorkspaceFiles(folder.uri, workspaceFiles);
			}
		}
	}