It gets rid of lines from unused lines of the EDU
I get this
23:36:20.880 [script.err] [error] Script Error in War_in_the_Middle_Ages/data/export_descr_unit.txt, at line 157, column 1
unrecognised armour sound type 'stat_heat 1
the line mentioned is where are is supposed to be. specifically the armour_ex line which was last removed by your file and now prevents me from loading up my game properly when I try [io] file_first rule. I have to go back and put this back in manually.