I am suggesting to name the repositories according to their actual function. If Extras-Testing is no longer being used for testing, but rather for general distribution of software (as it appears to be used now), then the word -Testing must be removed. On the other hand, if Extras is actually being used by people who want to be safe from untested software, as you suggested, then it makes sense to rename it to Extras-Safe to signify its new function. As you see, my proposal simply follows your original statement about the status of Extras.