Actually, they don't.

Thor has been merged with Xiph's Dalaa into IETF's NETVC effort, and both Cisco and Xiph are backing this.

NETVC is a next generation codec designed to replace H264, H265, and all future MPEG codecs with a system that is not user- and developer-hostile wrt licensing lock-in via (possibly invalid) patents.

Why not just use VP9 right now? I hated it but changed my mind recently, it's pretty nice and works on Chrome, if you don't need Apple device support (for example for storing and archiving surveillance camera footage or ripping library of DVDs and BluRay movies...) Or in the future AV1 which is Daala + Thor + VP10.