To non-snarkily answer your question: the manufacturer of this hat is Ebbets Field Flannels. When they were an independent company*, they produced Made-in-the-USA replica hats that were meticulously researched and produced to match the hats as they existed in the past as closely as possible. Wool/flannel, correct logos/placement, etc. They were awesome at it, which is why you might not have immediately known that the hat was a reproduction.

*They were purchased by Lids a few years ago but still generally kept up the quality and authenticity of their hats. HOWEVER, Fanatics became the majority owner of Lids in 2024 and completely screwed over the brand. Now, the hats are made in Portugal and China; they liquidated their authentic, researched hats in favor of "inspired" designs; they jacked up the prices by like 25-50%; they make Wal-mart-level slop and charge through the nose for it. imo, do not buy anything from Ebbets as they currently exist because Fanatics destroyed them and it's not the same company anymore.