Istio is for building a service mesh inside your network of microservices. This is about the front facing ingress to get into your services from the internet. It's closer to Ambassador (https://getambassador.io)
Istio provides a control plane and can be deployed to also provide you with a service mesh with a side car approach. Istio also gives you features like rate limiting, traffic shaping, authentication (tls mutual auth) and metrics out of the box. Contour is meant to solve the ingress problem by using Envoy as a reverse proxy. I think it will primarily be focused on doing that.
Ambassador is positioned as API GW instead of ingress controller. Contour is designed to be an ingress controller.
API GW also acts as ingress controller but has more features than ingress controller to manage the APIs.
Contour is comparable to Istio-ingress, nginx ingress controller or HAProxy ingress controller.
When linking to GitHub, please link to the readme. Without knowing anything about the project, that's what we'll read first, and the additional click needed in mobile is a waste.
Keep up the good work.