The Core Team has decided to embark on renaming of the master branch to main.
Changing the name to main will have a downstream impact on engineering automation, pull requests, and so on. Executing this change will involve careful planning to ensure a smooth transition. We will have more details coming soon. We are approaching this as the first step to improve the use of names and terminology throughout the Swift project.
Similarly, Apple announced a broad initiative — "Updates to Coding Terminology" — to revise the terminology used in APIs, documentation, and elsewhere. This change aligns very much in the spirit of that initiative.