only output of cell values, not cell code: repeat code as HTML
Yep: embeds are for embedding output. If you want to share an editable, view-sourceable notebook, we still recommend you just link to the notebook on Observable - that way people can also fork it if they want.
share link includes secret API key: presumably it is possible to modify the scene with the key ?
Nobody panic: you can’t modify anything with the key. It gives read permission only.