There are two areas that you need to change.
The text used in subscription emails mostly comes from the language file (see
Where is the language file?
). The English language file is located in
../language/en-GC/en-GB.com_kunena.ini and you will find in that file the following:
Code:
COM_KUNENA_POST_EMAIL_MOD1="A new post has been made to a category to which you have assigned as moderator on the"
COM_KUNENA_BBCODE_HIDE_IN_MESSAGE="This text is hidded from guests"
COM_KUNENA_POST_EMAIL_NOTIFICATION1="A new reply has been posted on the"
COM_KUNENA_POST_EMAIL_NOTIFICATION1_CAT="A new topic has been created on the"
COM_KUNENA_POST_EMAIL_NOTIFICATION2="You can unsubscribe from this topic by visiting it and clicking the Unsubscribe button near the top or bottom of the page."
COM_KUNENA_POST_EMAIL_NOTIFICATION2_CAT="You are getting this notification because of you have subscribed into category. Please visit the category to unsubscribe."
COM_KUNENA_POST_EMAIL_NOTIFICATION_MORE_READ="Please note that you will not receive any further email notifications for this topic until you log in and read it."
COM_KUNENA_POST_EMAIL_NOTIFICATION_MORE_SUBSCRIBE="Please note that you will not receive any further email notifications for this topic unless you subscribe into it."
You can change the text to suit your own purposes if you like.
The email, itself, is generated by PHP (but I don't know exactly where it is). You could start by looking at
../components/com_kunena/funcs/post.php and working your way from there. That's what I started to do but it was too complicated for me.