3 repeated files, which one is used for email layout?

Hi folks, I have noticed that SYM has the file symbiostock_emailer.php place in 3 different folders with the same content, they are:

1. wp-contentpluginssymbiostock_emailer
2. wp-contentthemessymbiostockincinstaller
3. wp-contentthemessymbiostockincinstallersymbiostock_emailer

I wonder which one is the one that really controls the sent registration email layout?

Thanks.