While https://developer.blender.org doesn't display a prominent readme,
other 3rd party hosting services do (github/gitlab/bitbucket).
People may stumble on these sites (searching blender git here, 2 of the top 4 results link to github for eg),
in these cases it's nice if they're directed to official development channels and have some basic useful information.
Suggested text (taken from blender.org, roughly following https://github.com/KDE/krita as a template).
While other sections could be added the intention is to link elsewhere and not include too many details here - adding maintenance burden.
Screenshot from github:
