CI steps can grow quickly, and when there are tasks that need to be done on all branches it would be better if you don't have to repeat them in the YAML file as that leads to potential problems. What I mean is probably best shown with an example:

You have a project and you want to run certain tests on all branches: lint checks, unit tests, and code quality, and maybe you need to compile it as well. This involves several commands to be run. In addition you have a staging branch that needs to automatically deploy for your QA team, and a master branch that needs to be deployed to your production environment.

With the current situation this means you have to write out all of the build steps for default as well as for the master and staging branches. It would be far better if there was a way to define the test/compile steps as global or shared steps that need to run for every branch. Maybe as part of a all: section or a flag for branches to (optionally) inherit from default.