Google AI explained it well
The NFL has reportedly passed a rule change allowing teams to declare onside kicks at any point in the game when trailing, not just in the fourth quarter. Additionally, onside kicks will be taken from the 34-yard line, and players on the kicking team will be able to line up with a foot on the 35-yard line, according to multiple sources. This change aims to improve the success rate of onside kick recoveries, which has been low in recent years.
Here's a more detailed breakdown of the rule change:
Flexibility:
Teams can now declare an onside kick at any point in the game if they are trailing.
New Line of Kick:
Onside kicks will be taken from the 34-yard line instead of the 35-yard line.
Kicking Team Alignment:
Players on the kicking team can line up with a foot on the 35-yard line, which is one yard closer to the receiving team.
No Surprise Onside Kicks:
Teams still need to announce their intent to attempt an onside kick before the play.