src/vs/workbench/contrib/debug/common/debugModel.ts/StackFrame/toString
class StackFrame:	toString(): string {
		const lineNumberToString = typeof this.range.startLineNumber === 'number' ? `:${this.range.startLineNumber}` : '';
		const sourceToString = `${this.source.inMemory ? this.source.name : this.source.uri.fsPath}${lineNumberToString}`;

		return sourceToString === UNKNOWN_SOURCE_LABEL ? this.name : `${this.name} (${sourceToString})`;
	}