# hdr_lines => string of various header lines for mode information
# mode_a => original mode of oid_a (string, not integer),
# ibx => PublicInbox::Inbox object containing the diff
-# smsg => PublicInbox::SearchMsg object containing diff
+# smsg => PublicInbox::Smsg object containing diff
# path_a => pre-image path
# path_b => post-image path
# n => numeric path of the patch (relative to worktree)