The Fight Against Fentanyl Act expands what state and local law enforcement agencies can purchase using federal grant money from the Byrne Justice Assistance Grant program. Specifically, the bill allows these agencies to use their Byrne JAG grants to buy fentanyl testing kits and opioid reversal agents like naloxone, which can reverse opioid overdoses. This measure is designed to help communities combat the fentanyl crisis by giving law enforcement and public health officials better tools to detect dangerous drugs and save lives. The bill does not specify additional funding amounts or implementation timelines, instead simply allowing existing grant funds to be redirected toward these public health purposes.