This repo contains a Dockerfile of an image with nginx and ngrep. It can be useful for viewing requests between services, that are talking to each other using HTTPS.
You can use this image for debugging purposes in a setup presented in the diagram above. In short, you can point your service (the red one) to HTTPS proxy container (created from this image - green) and then use ngrep on it to see the requests and responses it sends to the Service B.
More info: