Refocusing is a project mainly written in Coq, it's free.
A formalisation of the refocusing transformation by Danvy et al. in Coq
The source can be compiled using 'make'. It is known to compile correctly using Coq 8.2pl1.
Each part of the formalisation depends on the utils/Util module. The dependencies inside each part of the formalisation are as follows: