I'm guessing because it's impossible to inject files into? It used to be, and was annoying because the browser I was using you needed to put widevine in a spec

I'm guessing because it's impossible to inject files into? It used to be, and was annoying because the browser I was using you needed to put widevine in a specific location, but it was impossible to do so. They say it's for security, but to an end user it was just an annoyance.