-O[v], --describe-all-parameters : describes all the parameters. v makes this verbose, i.e., it gives a verbose description of all parameters.
When running the Einstein Toolkit executable with
--help, the above command-line option appears. The 19,123 lines of output is terrifying, but could be made less so. For one thing, each element of a parameter array is shown individually, and many arrays have 100 elements. I think the output for arrays should be combined into a single line.