The above was an ultra-hurried second draft attempt at getting posted, before it started, the basics about this programming. The lost draft was based on TCM's on-screen promo and their on-line schedule. I'm now in the midst of it and it is turning out differently from what the listings said.
I did, JUST BARELY, get it up, at 4:59 PST or so.
It seems that TCM is launching a Saturday morning slot of vintage matinee fare, titled "SATURDAY MATINEE ". :-! Right this moment, a John Wayne B-western is unreeling.