That's 'cause it's not there. It's one of those things we've been brainwashed into thinking we "know" -- you can only discharge a restricted firearm at an approved range -- which just isn't true. I shoot my handguns at Connaught a few times a year, which is NOT an approved range, as a for-instance. I have to get a special short-term ATT to do so, because it's not an approved range, but I am then technically discharging my restricted at a non-approved location. Why am I not arrested? Because nowhere in the CC does it say what people THINK it does. Including Bob, who keeps quoting the laws about possession and transportation as if it were about discharging the firearm.
There is no law that says you can only discharge a restricted at an approved range in the Criminal Code. You won't find it. I've looked, too, because I used to think I "knew" that was the law.
The ATT's are used to create the same effect, but do so based solely on possession and transportation, not discharge.