I can confirm that mine is 20 feet long. In my experience, it is designed to be long enough to be just a little short of “that” plug you want to connect to - isn’t that the design rule of the universe though?
I have carried a 50' UMC (I also own a 40 footer as well) for years. It was “stretched” with Mil-spec crimping by @TonyWilliams of quickchargepower.com. This eliminates some of the risks associated with excessive heat buildup at connection points as well as the risk of accidentally pulling too much amperage since many folks use an improperly terminated 14-50 extension cord that often requires manual intervention to set a safe charge rate and that also requires re-checking with every use since many cars in the past have “forgotten” after an update.