Specifying the application that automatically opens a particular type of file or link is a function built into the macOS operating system. This process allows users to determine which application is used when a specific file extension, such as `.jpg` for images, or a specific link type, such as `mailto:` for email, is activated. For example, one might choose to open all `.pdf` files with Adobe Acrobat Reader instead of the system’s built-in Preview application.
The ability to designate preferred programs enhances workflow efficiency and personalization of the user experience. Historically, operating systems would often assign default applications based on installation order or a pre-determined hierarchy, leading to potentially undesirable outcomes for users with specific preferences. The current mechanism provides granular control, allowing individuals to tailor application behavior to their needs, improving productivity and minimizing unnecessary steps.