One of the line numbering tasks is numbering lines within a group. Numbering starts with number 1. The numbering of lines within a group is defined by the LineThrough system variable.

in short,Line ThroughWhen using the system variable, every line in the rendered list has an index number, and starting to print a new group header does not affect the numbering (the numbering is reset to its initial state of 1 It will not be).