Yup, the hotfix predates the 5.6.5 JB release day by, err, a lot (it was originally released on the 17th of December, 201
4, to be exact). And the decision to rely on it and not reinvent the wheel also came pretty early in the actual elaboration of the format the release would take, so it wasn't a surprise to anyone involved

.
The hotfix post was even updated well before the actual public release to make sure everything would be ready on release day...