I'm not sure why lsmagic needs to return a JSON data structure by default - but the end result is that in JupyterLab, it becomes kind of useless... In Classic calling %lsmagic produces (clipped for simplicity):

while in Lab, this is the output:

Lab defaults to showing JSON reprs when available, which typically makes sense, so while this is a change in behavior re. Classic, I'm inclined to think it's a good step forward.

Users can get the text via

but that's a pretty awkward experience. Do we really need lsmagic to produce JSON by default? It seems to me that generating plain text would be fine most of the time, perhaps with a --json/-j option for JSON output when desired?