To put it another way
EBS is a Fancy Name for “web server” it’s just a HTTP server that will serve up HTTP requests.
Building an Twitch extension is like building a website, the only difference is that the front end and it’s assets are stored on a CDN, which some people do with normal websites with services such as AWS Cloudfront, or the independant Cloudflare.
TLDR: EBS = A Web Server, usually running NGINX or Apache.