The following fields merge information from the list the message is being sent through.
%%merge list.name%%
The short name of the list.
%%merge list.topic%%
The name of the topic this list belongs to.
%%merge list.descshort%%
The short description of this mailing list.
%%merge list.admin%%
The name of the administrator assigned to this mailing list.
%%merge list.urllist%%
The URL to the homepage of this mailing list (if any is defined).
%%merge list.urllogo%%
The URL to the GIF/JPEG graphic logo for this mailing list.
%%merge list.keywords%%
The topical keywords assigned to this mailing list.