Librarian: support for <abstrakt>

diff --git a/lib/librarian b/lib/librarian
index ff2a09e..28d85f1 160000 (submodule)
--- a/lib/librarian
+++ b/lib/librarian
@@ -1 +1 @@
-Subproject commit ff2a09e9ecd8e9bede2d3572942bcd32f66f6198
+Subproject commit 28d85f12957a4b8609b4f419e70dd42a22b57765