extensions/markdown-language-features/src/preview/preview.ts/DynamicMarkdownPreview/getPreviewTitle
class DynamicMarkdownPreview:	private static getPreviewTitle(resource: vscode.Uri, locked: boolean): string {
		const resourceLabel = uri.Utils.basename(resource);
		return locked
			? localize('lockedPreviewTitle', '[Preview] {0}', resourceLabel)
			: localize('previewTitle', 'Preview {0}', resourceLabel);
	}