Branching in programming refers to the use of decision-making structures within the code, which allows the execution flow to change based on conditions. When a programmer needs to add a new subroutine that operates under specific conditions within an existing application, branching (such as if-else or switch-case statements) would be used to integrate this new functionality seamlessly. This allows the application to execute different sections of code based on the requirements of the new product line.
Reference: Programming fundamentals, including the concepts of loops, branches, and functions, are often discussed in introductory programming courses and texts, which are also foundational components of IT education as per CompTIA's guidelines.