To reproduce:

1. Create a new project and then script
2. Try to access Tethers property through script
Note: Notice that there is none
3. Try to access ContinuousCollision property through script
Note: Notice that it's type of float although bool is expected
4. Try to access solverFrequency property through script
Note: Notice that it's type of bool although float is expected

Note: These properties in documentation are also invalid

Reproduced on Unity 5.3, 5.5, 5.6 and 2017
Not reproduced on Unity 5.4
Regression on Unity 5.5