SGE began as a Search Labs experiment in 2023, generating a summarized answer above the classic results. After testing, Google rebranded it and rolled it out as AI Overviews for general availability, starting in the US in May 2024.
If you still see "SGE" in older guides, read it as AI Overviews. The optimization goal is unchanged: be one of the sources the overview cites, which depends on clear, helpful content rather than any special markup.