1 files changed, 2 insertions, 0 deletions
diff --git a/lib/PublicInbox/Search.pm b/lib/PublicInbox/Search.pm
index fabf5301..86a6ad67 100644
--- a/lib/PublicInbox/Search.pm
+++ b/lib/PublicInbox/Search.pm
@@ -316,6 +316,8 @@ sub qp {
                  my $user_pfx = $self->{-user_pfx} = [];
                  for (@$altid) {
                          # $_ = 'serial:gmane:/path/to/gmane.msgmap.sqlite3'
+                        # note: Xapian supports multibyte UTF-8, /^[0-9]+$/,
+                        # and '_' with prefixes matching \w+
                          /\Aserial:(\w+):/ or next;
                          my $pfx = $1;
                          push @$user_pfx, "$pfx:", <<EOF;