There are two protocols in use as of today for talking with the compositor: agl-shell which is intended for the shell, or in this case, homescreen (if we're talking about qtwayland) or WAM if we are talking about HTML5 type, and agl-shell-desktop, intended for regular apps to receive application notifications (when they are started) or to able to set additional roles to surfaces (like pop-ups). 

Some helpers for Qt and WAM could be useful to avoid all the bind/register/events hassle. Not really necessary but could be a nice thing that have.