Depending on the brand, the modern stuff is fatback, brined...and then sometimes smoked. Sometimes it's also dry cured, then smoked.
The salt port that we should be using (imho), while not being the best parts of the pig, should be meatier than what you often find sold for use as an ingredient for other dishes, like baked beans...
One important tip...you must weigh down the top pieces in whatever you're using to hold the brine when wet curing...you want the salt to soak into the meat, and exposure to air, even in a sealed container, may allow that bit to spoil in the future.
I was taught that when using liquid cure, you don't pour it in hot as they do in the Townsend video, as that would cook the meat, and you're not trying to cook it...PLus you're supposed to heat up the brine and dissolve the salt until the solution will no longer dissolve added salt...it is then saturated...allow it to cool, then pour it over the meat in the container...so you use only that to brine the meat...adding layers of dry salt, then adding a saturated brine would simply waste the dry salt...
LD