I'll venture an educated guess .
Check Pectoral . Also known as special grind .
Sits on top of the brisket , gets trimmed off .
Usually come 6 to a bag where I get them .
View attachment 718294
Looks like this right out of the bag ,
View attachment 718295
After cleaning / trimming ,
View attachment 718297
View attachment 718296
I know not the brisket you wanted , but it's a good useful cut of beef .
Here's a couple ways I use it ,
Overnight dry brine . Grilled hot and fast .
View attachment 718298
Slice across the grain .
View attachment 718299
Roast beef and gravy ,
View attachment 718301
Makes good grind too . Chili , burgers , or pasta sauce .
View attachment 718302
View attachment 718303
If you buy " stew " meat at the store , good chance it's chuck pectoral .
Same with ground beef .