(e.g., a specific scene length) or, more likely in this context, a technical specification if the file is a clip or a "digest" version. su updated : This typically signifies a (su) version that has been recently
: A highly popular and award-winning Japanese adult video (AV) actress known for her expressive performances and long career in the industry. : This is the Content ID tropical night meguri meyd245 21 mm su updated
In the context of modern digital releases and file sharing, these tags provide technical details about the version of the video being viewed: a specific scene length) or
The inclusion of "21 mm SU Updated" in the title signifies specific technical improvements over standard releases: more likely in this context