%capture --to var current capture output from a cell, optionally parse it as json or csv, and save the results to var. I just had a case where I would like to capture output from multiple cells to a variable so something like

%capture --append var

would be useful.

Here --append var would be equivalent to --to var is var does not exist. Otherwise --append var will append the captured text to var, with type matching type of existing var. That is to say, text to text, DataFrame appended to DataFrame ...