Other packages depend on ttf-dejima-mincho which is now gone:
https://release.debian.org/migration/testing.pl?package=iceweasel

I believe fonts-dejima-mincho should provide ttf-dejima-mincho until
coordinated with reverse dependencies on migrating away from it.

 - Jonas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=UUoC
-----END PGP SIGNATURE-----

control: reassign -1 iceweasel

 Its debian/control.in depends fonts- | ttf- , so it shouldn't prevent
 migration, IMHO.

 Anyway, here's a patch for it. Could you check and apply, please?

--- iceweasel-38.4.0esr.orig/debian/control.in	2015-11-04 07:12:54.000000000 +0900
+++ iceweasel-38.4.0esr/debian/control.in	2015-11-27 06:50:44.560156570 +0900
@@ -59,8 +59,8 @@
                xfonts-base,
                xauth,
                ttf-bitstream-vera,
-               fonts-freefont-ttf | ttf-freefont,
-               fonts-dejima-mincho | ttf-dejima-mincho,
+               fonts-freefont-ttf,
+               fonts-dejima-mincho,
                imagemagick,
                librsvg2-bin,
                xsltproc,