The tutorials on the Mapstraction site currently show a http://mapstractions.com hosted version being used rather than suggesting developers download and host it themselves.
Whilst this is convenient, it's currently served from Github and we have no SLA with them and there are no guarantees this hosting wont just disappear one day breaking a lot of people's sites.
It would be good to get a version up on cdnjs and update the examples in the tutorials to point to that as soon as possible.