WASHINGTON (AP) — President Joe Biden on Saturday signed the most sweeping gun violence bill in decades, a bipartisan compromise that seemed unimaginable until a recent series of mass shootings, including the massacre of 19 students and two teachers at a Texas elementary school.

Here are the highlights of the gun violence bill:

—Expanded background checks: State and local juvenile and mental health records of gun purchasers will be part of federal background checks for buyers age 18 to 20. Three-day maximum for gathering records will be lengthened to up to 10 days to search juvenile data. If 10 days lapse without a resolution, the sale will go through.

—“Boyfriend loophole”: Convicted domestic violence offenders will be denied guns if they have a current or past “continuing serious relationship of a romantic or intimate nature” with victim. Abusers’ right to buy firearms will be restored after five years if no additional violent crimes are committed. Firearms are currently denied to domestic abusers if they are married, live with or had a child with victim.

—Red flag laws: Federal aid will be given to the 19 states, plus the District of Columbia, that have laws helping authorities get court orders to temporarily remove guns from people deemed dangerous. Those states will need strong processes for challenging the taking of firearms. Other states could use money for crisis intervention programs.

—Mental health: The bill will expand community behavioral health clinics, help states bolster mental health programs in schools and provide more mental health consultations remotely.

—Education: The bill will increase spending on school mental health, crisis intervention, violence prevention programs, mental health worker training and school safety.

—Federally licensed gun dealers: Current law requires that people “engaged in the business” of selling guns be licensed, which means they must conduct background checks. The bill defines that as selling firearms ‘‘to predominantly earn a profit,” in an effort to prosecute people who evade the requirement.

—Gun traffickers: The bill will create federal crimes for gun traffickers and “straw purchasers” who buy guns for people who would not pass background checks. The penalties are up to 25 years in prison. Such offenders are now primarily prosecuted for paperwork violations.

—Cost: The nonpartisan Congressional Budget Office estimates the cost of the bill at $13 billion, mostly for mental health and schools. That is more than paid for by further delaying a 2020 regulation that’s never taken effect requiring drug manufacturers to give rebates to Medicare recipients. That regulation would increase federal Medicare costs.