"Your" project is a project you happen to make any changes at. Any Readme can contain also extra parts, specific for a project.
Underneath is a template you can use in a project without any (or with scaffolded) readme:
What this project is about, what problem it solves. General description.
How to run project locally
How bug fixes are named? How feature-branches are named? Where pull requests should go (straight to master, develop branch)?
How to deploy project
How to test project (URLs in different envs should go here)
If project has some specific alerts, monitoring dashboards or logs, put it here
If project directly relates to some other projects, put links here