Get the table schema as json?

I wanted to extract the schema of the table as json, but I noticed that the Python and R packages apparently only output the schema as a single string.
So I had to parse a string, but if a method was implemented that would output a dictionary or a list from the schema, I would use that.

The issue does not name files, tests, or an entry point. Start by locating the existing table-schema output APIs in the Python and R packages, then determine how a structured dictionary or list should represent the schema and add coverage showing that the structured result is returned instead of only a string.

Written by the indexing model from the issue text.