As announced on Xiph's website and in a message to the vorbis-dev mailing list. Tremor is an integer-only Vorbis decoder library. Previously source for this product was not available, but it has just been relicenced under the same licence terms as the rest of the Vorbis libraries.
This is very good news for anyone looking to create Vorbis decoders on hardware without good support for floating point (the standard Vorbis libraries utilise floating point extensively).