Which software CDNs are using

Anything with a question mark means I'm not 100% sure
CDNs that belong to the same company but are known by other names are listed separately. i.e. Edgio/Edgecast/Layer0

Links to the cdns and software have been linked below

Cloudflare      Pingora? -> Pingora? (formerly NGINX/Open Resty)
Azion           \ NGINX -> Apache Traffic Server?
Bunny           \ NGINX
Google Cloud CDN Envoy? -> ?
Keycdn          nginx -> ?
Imperva          ? -> ?
CDN77           \ NGINX
Gcore            \ NGINX? -> NGINX
Stackpath        \ HAProxy -> Varnish
Vercel           \ NGINX? -> Varnish
Reflected        \ ? -> ?
HAProxy          \ ? -> ?
Fastly           \ ? -> Varnish
CDNetworks       \ ? -> NGINX
Akamai           \ NGINX? -> Squid
Cloudfront       \ NGINX -> Squid
Edgio          HAProxy -> Varnish
Edgecast       HAProxy -> Varnish
Layer0          ? -> Varnish
Cachefly         NGINX -> Varnish

Not accessible
Apple - ? -> Apache Traffic Server

H2O
Open Source: https://github.com/h2o/h2o

Varnish Cache - Fastly, Vercel, Edgio, Edgecast, Stackpath
Open source: https://varnish-cache.org/
Premium: https://www.varnish-software.com/

HAProxy - Stackpath, Edgio, Edgecast
Open source: https://www.haproxy.org/
Premium: https://www.haproxy.com/

Pingora - Cloudflare
Open source: https://github.com/cloudflare/pingora
(not quite yet)

Squid - Amazon Cloudfront, Akamai
Open source: http://www.squid-cache.org/

Tengine - Tiktok, Alibaba, Tencent
Open source: https://tengine.taobao.org/

Open Resty (NGINX) - ?
https://openresty.org/en/

Apache Traffic Server
Open source: https://trafficserver.apache.org/