This modifier aligns child path lines if the parent path lines are strongly curved. This modifier applies to the parent path and before modifiers that curvature the path lines. See the connection graph below.
The right connector allows to connect the Distributors node for child pathlines.
By connecting distributor node to this connector, you can specify which child branches are aligned.
Percentage value, showing how strongly the child paths aligned. 0% - not aligned, 100% - fully aligned.
The right connector allows to connect the Curve node to control the Amount value along the pathlines.
Align children is not used:
Align children is used with Amount = 100%: