I like horse steak. It's nice meat, even if lean, because it isn't dry or tough (when properly cooked). I can't relate to it as old fashioned though. More regional, I'd say.
Last time I had it was in Verona where it's fairly common dish.

It's old fashioned in the US. It was fairly common during World War II, or such is my understanding, and then almost disappeared. it was on the menu at Harvqrd Faculty Club from WWII until the 1980s, I believe. it would be almost as hard to find here now as camel.
I ate horse steak tonight.
I'm not sure, but I think that I ate horse meat when i was a child. A report published in 1952 disclosed that organized crime had sold 4.5 million pounds of horse meat in Chicago during the preceding two years. The horse meat was ground up, then used to adulterate ground beef by as much as 40 percent. Much of the adulterated meat was sold to institutions such as schools, which used it in meatloaf. Our school had meatloaf on the lunch menu almost every day, and I chose it often.

Fieldgate, in a recent thread, I forget which, you were talking about eating chicken stomachs. i wonder if you were thinking of gizzards, which are a digestive organ but distinct from the stomach.

NA, when I was a child a NYC chain of butchers called Merkel's went out of business when it was revealed they had mixed kangaroo into their ground beef.
I imagine that kangaroo meat sells for more than beef these days.
When I was a kid, we had a pet red-tailed hawk (don't ask). My father would buy horse meat, which was sold at groceries as dog food, to feed the beast.
My father would buy horse meat, which was sold at groceries as dog food,
One man's trash is another man's treasure
Vinny, #114
I can't say for sure. I remember on another thread (or was it this one?) gizzards and giblets being discussed. To be honest, I didn't follow it so I'm not sure about the difference.
All giblets are still common in Poland, and there're several dishes you can make from them. If you ask me, they're nice dishes, the meat is firm but tender. Usually made in a creamy sauce.
Here are a few recipes , regretfully in Polish, but you can see the dishes made from chicken or turkey stomachs in the pictures (except for the last two).
What I find interesting is that Google, on translating the second recipe, translates the first ingredient, 1kg żołądków drobiowych, as "1kg of chicken gizzards," but everywhere else in the recipe it is translated as stomachs, including the name of the recipe, "Chicken stomachs in dill sauce."