Files with the extension '.ris' are understood to contain RIS bibliographic data, which can be parsed to appropriate system attributes in the References group. This improves the handling of references to journal articles and conference proceedings imported from Bookends, Zotero, and other sources of RIS data.
From v9.3.0, with RIS import $Authors was previously sorted in alphabetical order, but now respects the order in which the authors are listed in the reference.