Why do I need to change IE settings to enable HTTP/2 on Windows 10?

Question

I recently enabled HTTP/2 on a site I was developing.

To do this I had to

1. Be on Windows 10
2. Use a browser that supports HTTP/2 (in my case Chrome)
3. Configure my webserver (iisexpress) to serve the site using https
4. Enable HTTP/2 in the Internet Explorer options

It all works, but I'm confused about why 1 and 4 are necessary. Especially 4 as I'm not actually using Internet Explorer. Now the above link suggests that it has something to do with the WININET library and I understand that IE options occasionally affect settings in the operating system itself but that's where my understanding abruptly stops.

What does the operating system even have to do with any of this? Isn't http/2 just between the browser and server application? Are there system resources being used by IIS? Does that mean if I set up something like Katana or nginx I could use HTTP/2 without Win10 or toggling the IE setting?

Clearly

Answer 1

Disabling of HTTP/2 in the Internet Explorer options (it's enabled by default):

have relation only on IE11 on your Windows 10 computer. Chrome and even Microsoft Edge can still use HTTP/2 to communicate with your IIS (I tested with IIS instead of iisexpress). You can verify that using Developer Tools. You should only clear the browser cache to see that H2 (HTTP/2) be used during the communication:

Halloo