Thanks for the wayback machine link Andrew.  I read it, understood it, and will comply.

Joe, those test cases look great and the outputs are the same as `jq`.

As for forward slashes being escaped, I found this: https://stackoverflow.com/questions/1580647/json-why-are-forward-slashes-escaped.

Forward slash escaping is optional, so not escaping them in Postgres is okay.   The important thing is that the software _reading_ JSON interprets both '\/' and '/' as '/'.