Currently, imports of nodes with a body_format that doesn't exist work fine, in the sense that no error or warning is given and the body_value is imported correctly, but the field will be blank on the UI until you manually edit the node, select (one of the existing, on this site) text formats, and save it (or ofc after you import/create a text format with the same name and re-save the node).
It would be nice to have a warning message for the user after the import, like:
Node [title] had a missing [text_format_name] on its [field_name] field. Either import the text format from the origin site and re-save it to see it as originally intended, or manually edit it and select one of the available text formats.
And some additional settings at /admin/config/content/single-content-sync to decide what to do in these situations, like:
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1.4
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