There was just a discussion about this on the tomato forum (link below). See particularly, Carolyn's response. I don't know if they are as proprietary with other plants, of if this is particular to tomatoes. But it could explain why you can't find the information.

Here is a link that might be useful: Big Beef

Knowing the parentage will not help you.

Yes if a hybrid is grown from seed the seed will likely be viable, but you will never know what you are going to get especially if it is open pollinated. It may revert back to the parent. It may be like the hybrid or nothing like the parent or the hybrid. It may be like another species that was the pollinator. It may have been self pollinated or not at all and will produce small flowers or not be viable.

When growers produce hybrid seed, they are hand pollinated from a like species when the flower is in bud, and then covered with mesh bags so no insect can pollinate them. They are left until the seed falls into the bag.

If they are started from cuttings they will always be true because you are growing a piece of the original plant

As someone who works in the industry, I can tell you that the commercial breeders of hybrid flower seeds will NEVER disclose the exact parentage of their hybrids. That is proprietary info and closely guarded.