https://player.vimeo.com/video/752065573?h=57cd1cfcdb&badge=0&autopause=0&player_id=0&app_id=58479
Animation showing visible constraints connections (the yellow lines) in Custom mode.
The Weight setting alters the influence each constraint type provides to the overall, global solution; here it relates to the birth constraints.
If you are only using one layer, this can be left at the default, 100%.
If you are combining different constraints in several layers, you could reduce this weight to lessen the effects of the connections and blend in other layers.
If enabled, this only makes connections between particles born at the same time.
Demonstrating the enabling of the Only Born checkbox, during an animation.