A OGRE mesh can be used to store a skeleton, mesh, materials and scene information. The skeleton and mesh information can quite large and hence they are typically stored in the OGRE binary format. If you would like to view the internal values, there is an alternate OGRE XML format that is supported too. The OgreXmlConverter tool can be used to convert the skeleton and mesh files between the binary and XML formats.
To install the OgreXmlConverter:
$ sudo apt install ogre-1.8-tools
To convert a skeleton from binary to XML format:
$ OgreXmlConverter foo.skeleton foo.skeleton.xml
To convert a mesh from XML to binary format:
$ OgreXmlConverter foo.mesh.xml foo.mesh
Tried with: OGRE 1.8.0 and Ubuntu 14.04