“2-yr mean citedness” is the OpenAlex field summary_stats.2yr_mean_citedness (CC0): mean citations per paper over a two-year window. It is a raw bibliometric field, not a journal rating, and is not used for default ranking.
Social Sciences99Arts and Humanities22Computer Science11Auxiliary sciences of history: Diplomatics. Archives. Seals1Bibliography. Library science. Information resources1General Works: Museums. Collectors and collecting1