I think this is not correct, the line with the
#MNU_1.0 is like a control check just to know the info that comes next is valid, when we remove it (and the firmware tryes to load the fish) it gets an error
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The other way is to really delete the file (so the .elf cant find it), to do this you need to delete the line for it in the xml control file located at root of the extraction path when you choose [Extract All] in XForge
As probably you realized at this point in the few days you has been using XForge that rebuilding method is inspired in rcomage

First you extract all (and it creates a xml control file)... and then that control file is the "boss" that is used when XForge builds the QRC file
So you know... is just a matter of deleting the line where appears the name lines.qrc/override/day/PARTICLES.mnu inside the xml control file... and when you create the QRC is ignored completly (not included in the QRC)