The manufacturing world is very interesting. There are so many layers to suppliers, it's amazing. I worked for a contract manufacturer over here on the East Coast that makes parts for the auto industry. Except they sold the parts to a company, who put them in an assembly, who then sold those assemblies to another supplier, who then finally put them in a completed chunk to sell to the OEM. That same contract manufacturer made major components of precision tools (in some cases, nearly the entire tool) for a U.S.-based precision tool manufacturer.
You see the same thing in the tool world. Brands like Tekton and Astro Pneumatic rely almost exclusively on contract manufacturers. Sometimes those manufacturers make tools for other brands as well. I will say there is a difference between using a contract manufacturer and having them make you a customized/bespoke tool vs. just purchasing and rebranding a tool.
Many brands simply flip through the pages of Alibaba and order 10,000 of a certain tool and stamp their logo on it. No customization at all.
The straight rebrands are usually pretty easy to figure out, but the customized tools are a bit harder. Sometimes the secondary company is forthcoming about the OEM, other times people figure it out through shared design components with other tools, or look at shipping manifests and so on.