The Help page Physics/tensors-a complete guide states that spacetime metrics from Kramer et al. are referenced by chapter, section, and equation number, e.g., g_[[12, 16, 1]]. But there is no section 16 in Ch 12 and equations within each chapter are numbered sequentially without reference to section. By playing around it seems that in fact the first number is chapter, the second number is equation number, and the third number refers to subcases of the metric, when they are specified in the text. Is that correct?
Also, the output I get from say g_[[27, 27, 1]], or any other attempt made, is just the metric, without any specification of the coordinates etc, which the Help pages susggest should be part of the output.