I think synthetic ~ synthesized in this context, as opposed to "not real".
Sense 4a1 here, not 4c: https://www.merriam-webster.com/dictionary/synthetic
Sense 4a1 here, not 4c: https://www.merriam-webster.com/dictionary/synthetic
Without anything redacted, definition 4b is "devised, arranged, or fabricated for special situations to imitate or replace usual realities"?