The California Supreme Court released its opinion (185-page PDF file) in regards to the challenge to Proposition 8 which amended the state constitution to state “Only marriage between a man and a woman is valid or recognized in California.” The task for the court was to determine if the initiative was a proper constitutional amendment and they decided it was. However, as courts often do in their decisions, they spell out exactly what is and isn't covered by the law.
The scope of the exception created by Proposition 8, however, necessarily is determined and limited by the specific language and scope of the new constitutional provision added by the ballot measure. Here the new constitutional provision (art. I, § 7.5) provides in full: “Only marriage between a man and a woman is valid or recognized in California.” By its terms, the new provision refers only to “marriage” and does not address the right to establish an officially recognized family relationship, which may bear a name or designation other than “marriage.”