How to find the default variables for each github action variable

Looking at the documentation, it statest that each triggered action has a set of default variables, how do i see these default variables for each action type?

For example i noticed i can use this variable for a comment created action:
github.event.comment.body

https://help.github.com/en/actions/automating-your-workflow-with-github-actions/using-environment-variables

According to your example, if you want to get some information from github.event, github context is more suitable of your requirement . You could add this step to your workflow:

- name: Dump GitHub context

  env:

       GITHUB_CONTEXT: ${{ toJson(github) }}

  run: echo "$GITHUB_CONTEXT"

Then you can see the github json body in logs.