There are a grand total of 4 questions tagged with expanded-universe, 3 of which are about Star Wars while 1 is about Mass Effect.
According to the tag wiki, it is intended for
Generally, expanded universe is the extension of a media franchise (i.e. a television show, series of feature films, etc.) with other media (generally comics and original novels), often with the result being that the stories described in the other media are not considered canon in the original.
With reference to Star Wars: The Expanded Universe (or EU for short) encompasses every one of the officially licensed, fictional background of the Star Wars universe, outside of the six Star Wars films produced by George Lucas. It is derived from and includes most official Star Wars-related books, comic books, video games, spin-off films, television series, toys, and other media. This material expands and continues the stories told in the films, taking place anywhere from over 36,000 years before The Phantom Menace to 134 years after Return of the Jedi. The issue of which aspects are canon is one of the most hotly debated topics among fans. (Wookieepedia)
This would classify it as a meta-tag.
Also, there are a further 51 questions that are not tagged with it, but that do contain the phrase "expanded universe", 11 of which are not about Star Wars (most of those are about Star Trek).
So what, if anything, should be done?
There is a tag star-wars-eu that's already used on 11 questions. Should all questions tagged star-wars + expanded-universe be retagged to that, while all questions containing "expanded universe" and tagged with star-wars should be checked and possibly retagged as well?
Do we need a tag star-trek-eu for those 9 or so questions containing "expanded universe" and tagged with star-trek?
Should we remove expanded-universe from other questions?