No maintenance required or possible on the canister.
The black box guess is pretty funny!
They typically fail by coming apart on the inside and get clogged,sometimes contaminating or ruining the vent valve and/or purge valve depending on the system,setting an EVAP related DTC.(Diagnostic Trouble Code). Hopefully many many years from now.
It could be located anywhere,it is a matter of routing thick and thin vapor/vacuum lines between tank,canister,purge valve,vent valve plus electrical wiring etc.
Most trucks and SUVs have it near the tank and I can not remember seeing one under the hood of newer cars. I guess older cars had them under the hood.
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View my fuel log 2014 Mirage DE 1.2 manual: 66.3 mpg (US) ... 28.2 km/L ... 3.5 L/100 km ... 79.7 mpg (Imp)