"Feel the Flash" might be the name of the mod or flash game. "Hardcore" could indicate a more challenging or intense version. "Kasumi" is likely from the Dead or Alive series, so this could be a character mod adding Kasumi to Street Fighter IV. "Rebirth V31" might be the version number, so there's been an update. "English Translated" suggests that the mod has been translated from another language, probably Japanese, since Street Fighter is Japan-based. "42 Extra Quality" is a bit confusing. Maybe it's referring to the number of additions or extra content?