To delete a repository from Google Cloud Source Repositories:
Open the source view in the console:
Click the More button next to the repository you want to delete.
Enter the name of the repository where prompted and then confirm deletion.
From the command line, call:
gcloud init gcloud source repos delete [REPOSITORY_NAME]
The response looks like:
If [REPOSITORY_NAME] is deleted, the name cannot be reused for up to seven days. Delete "[REPOSITORY_NAME]" in project "gcloud-test" (Y/n)? y Deleted [REPOSITORY_NAME].