The porn video tag "theyear199x" refers to content that is set in the year 199X. This could mean that either the scenes, costumes or storyline of the video are portraying a specific time period, most likely the 1990s. Often this can be used as a descriptor for nostalgic scenes that take place during this decade, showcasing hairstyles, fashion, and technology from that era. The X in "199X" is used to represent any year within the range of 1990-1999, indicating a general timeframe rather than a specific year.