+formats or a non-standard database backend. Currently, lei
+uses L<Mail::IMAPClient> which has acceptable performance
+over low-latency links. Performance over high-latency links
+is currently poor.
+
+=head1 eml
+
+A single raw message file. C<eml> is not an output format for lei,
+but accepted by as an C<--input-format> (C<-F>) for read-only
+commands such as L<lei-tag(1)> and L<lei-import(1)>.
+
+Since C<eml> is the suffix for the C<message/rfc822> MIME type
+(according to the C<mime.types> file), lei will infer the type
+based on the C<.eml> suffix if C<--input-format> is unspecified
+
+C<.patch>-suffixed files generated by L<git-format-patch(1)>
+(without C<--stdout>) are C<eml> files with the addition of an
+mbox C<From > header. L<lei(1)> removes C<From > lines to treat
+them as C<eml> when reading these for compatibility with
+C<git-am(1)> and similar tools.