Apparently in the town of Windsor (a city no one has ever heard of, in Ontario, a province of Canada), some people like to eat pizza with shredded pepperoni on it, instead of round slices of pepperoni. In all other respects their pizza is normal pizza: round, sliced radially into wedges, with the familiar inter-pizzeria variations of, like, the herbs and spices in the tomato sauce, or where they get their cheese or exactly what combinations of cheese they use, or what other toppings they like to pair with the shredded pepperoni. It is just normal pepperoni pizza, but the pepperoni is shredded.
Some sources also claim that canned mushrooms are a Windsor-specific thing, but according to the Windsor Public Library, "Shredded pepperoni is what makes a true Windsor pizza different from other pies." And in any event, mushrooms, like pepperoni, are a totally normal pizza topping! We are talking about normal pizza with normal toppings, here, only with minor modifications to those two toppings.
Does this mean that normal pepperoni pizza, but with the pepperoni shredded (and possibly with the mushrooms canned), is in fact properly referred to as "Windsor-style pizza"? No it does not! At most you can say that it is "Windsor-style pepperoni." Normal pizza, with normal toppings, but with one of them shaped differently, is not enough to amount to a regional "style" of pizza. You cannot be out here in the pizza streets, mulching a totally ordinary—the most totally ordinary!—pizza topping such as pepperoni, putting it on your in-all-other-respects-utterly-normal pizza, and being like "Ah yes, this distinguishes the pizza-making traditions of our region." No the hell it doesn't! If "the same-ass pepperoni as you can get anywhere else in the freaking world, only we went at it with a pair of scissors first" distinguishes the pizza-making traditions of your region, your region has no pizza-making traditions.
Here is the correct formula for determining whether your region's pizza is a distinct regional style. A distinct regional style of pizza deviates from familiar pizza if and only if it:
EITHER
A) Reflects the peculiar historical pizza-making constraints of the region, like if something about its geography prevented ready access to flour for 200 years, so early Neapolitan immigrants had to make due with fish skin instead, and now everybody in the region enjoys pizza that has fish skin in place of flour-based crust, even now that modernization has made normal pizza accessible to them;
OR
B) Reflects the unique culinary and cultural heritage of your area, like if the early happy blending of Italian and Danish cultures led to the advent of local pizzas topped with traditional smørrebrød toppings such as pickled herring, pork liver paste, and mayonnaise mixed with peas, and now that's just how everybody takes their pizza in your region;
AND
C) Is pretty uniform across numerous unaffiliated pizzerias spread across either an entire dense major metropolitan area or a vast geographical region, like Siberia;
AND
D) Would be instantly recognizable as sharply divergent from normal pizza—and perhaps even bizarre and alarming—to a new visitor to your region, like for example if they ordered a pizza and were served a pork liver paste and pickled herring smørrebrød pizza with mayonnaise and smashed pea sauce on a crust made of the skin of a fish.
As you can see from these criteria, "normal pepperoni pizza, but with the pepperoni chopped into little thin shreds" does not qualify as a distinct regional style of pizza—unless someone wants to make an argument that the fine people of Windsor are characterized by their fear or inability to chew a very thin slice of cured meat, and that for this reason shredded pepperoni reflects a unique constraint on pizza-making in Windsor. Even then! Nothing about that pizza would strike any but the most fanatical pizza traditionalist as particularly unusual. They might spend two seconds going, Ah. Shredded pepperoni. Kind of neat! and then they will just move on with eating the pizza. They will not even be prompted to wonder whether this is a local thing.
The thing is, it is fine for a given region to have no particular unique style of pizza! Many fine cities and regions do not have their own styles of pizza. In many of those places, you can in fact get a perfectly good slice of pizza—they are fine pizza areas. On the other hand, at least a couple of cities (Detroit; St. Louis) do have their own styles of pizza, but their styles of pizza are silly and do them no particular credit. Having a regional style of pizza does not make a region fancier or cooler! When you strain to call "normal pizza but with the pepperoni carefully cut into letters spelling out 'CHEWING IS SCARY BUT YOU CAN DO IT SWEETIE'" a distinct local style of pizza, that is just a weird expression of insecurity and thirst. You're better than that!
In a just and sane world, there would be a formal International Pizza Certification Board to rule on these matters, to spare podunk localities the trouble of wrestling with the question of whether their honestly-kind-of-cute local conviction that pizza is best when oval-shaped thus makes oval-shaped pizza in fact "Fartburg-style pizza," and to punish regions that try to pass off "normal pizza, but with slightly more oregano than usual in the sauce" as their own distinct style of pizza. And that board would be staffed by me, personally, and no one else, and eating pizza all day and then being rude about it would be my job.
