User-defined params (from workflow YAML) were silently replacing the built-in commit/branch/actor params. Now both are merged into a single sorted slice, with user params taking precedence on name collisions so callers can still override the defaults when needed.
I was not really sure about this one though, as I wasn't sure if silently replacing the built-in is intentional or not in the design. For me it doesn't necessarily make sense to silently replace it but..