The graylog marketplace does not list the posted year of an item - only the day, month, and time. It’s not possible to understand the age of a content pack or plugin. The current display is just as useless as no date at all. An item could be from 2015 or 2017, but you wouldn’t be able to tell.
Hopefully this is just a web front-end issue and not a lack of information in the DB!
Actually, the more I browse the community, the more I notice this issue. Even this forum itself apparently has this problem.