SACRAMENTO, Calif. — Phillips 66 plans to build the first pipeline to bring gasoline and other refined fuels into California, a move that could challenge the dominance of the state’s established refiners and give fuel buyers another source of supply. The international energy company announced the project in August. California has relied for decades on fuel produced by in-state refiners, and the proposed pipeline could loosen their grip on a market that plays a major role in the state’s energy politics. Phillips 66 is also breaking with parts of the industry’s political establishment. The company left a powerful oil industry association last year, adding to signs that major players are no longer presenting a united front in disputes with Gov. Gavin Newsom and state policymakers. More competition could help broaden fuel supply in California, though the available project details do not establish a construction timeline, route or expected effect on prices. The proposal’s significance will depend on whether it advances and how much fuel it ultimately delivers. California’s dependence on local production has made the state’s fuel market especially consequential for consumers and policymakers. A new pipeline could alter that balance, even as the broader fight over oil’s future in the state continues.