+@vindex debbugs-gnu-suppress-closed
+The user option @code{debbugs-gnu-suppress-closed} controls, whether
+closed bugs are shown in the initial list.
+
+@vindex debbugs-gnu-mail-backend
+The user option @code{debbugs-gnu-mail-backend} controls the
+presentation of email messages produced by typing @kbd{@key{RET}} or
+by clicking the mouse on a bug: if its value is @code{gnus}, the
+default, a GNUS ephemeral group for that bug will be shown; if its
+value is @code{rmail}, the command will present an Rmail folder
+instead.
+