Box 1: subscribe -
To start monitoring all Git repositories in a project, use the following slash command inside a channel:
/azrepos subscribe [project url]
Box 2:
https://dev.azure.com/contoso/contoso-app
You can also monitor a specific repository using the following command:
/azrepos subscribe [repository url]
The repository URL can be to any page within your repository that has your repository name.
For example, for Git repositories, use:
/azrepos subscribe
https://dev.azure.com/myorg/myproject/_git/myrepository
Reference:
https://docs.microsoft.com/en-us/azure/devops/repos/integrations/repos-slack