“Test” environment is the domain of prototype cars driving at the proving ground. It is an internal affair, only for employees and contractors. The software is compiled on some engineer’s laptop and uploaded on the ECU by an engineer manually. No two cars are ever the same, everything is in flux. The number of cars are small.
“Production” is a factory line producing cars. The software is uploaded on the ECUs by some factory machine automatically. Each car are exactly the same, with the exact same software version on thousands and thousands of cars. The cars are sold to customers.
Some small number of these prodiction cars are sent for regulatory compliance checks to third parties. But those cars won’t become suddenly non-production cars just because someone sticks up a probe in their exhausts. The same way gmail’s production servers don’t suddenly turn into test environments just because a user opens the network tab in their browser’s dev tool to see what kind of requests fly on the wire.