Thank you for taking time to answer me.
No, I don't. This question is specific on how display all articles titles in the email subject.
jvstratum answers with this line :
jvstratum {autoarticle:99-| display:title| order:id,desc| datefilter:onlynew| min:0}
AcyMailing gave me this line after creating my first automatic email. Most of the time, there is one article to send, sometimes 2 articles to send. In that case, the email subject is empty ?!?