Ans: main.
Tip: If you want to init a repo locally that has a default branch with branch name main rather than master then make sure to add this config:
$ git config --global init.defaultBranch main
The apparent overhaul of Github terminology comes amid nationwide protests calling for an end to systemic racism and police brutality following the killing of George Floyd in Minneapolis, Minnesota, on May 25, 2020.
The computer industry's use of the terms master and slave caught everyone's attention in the summer of 2020. Amid the many protests and the growing social unrest, these harmful and antiquated terms were no longer considered appropriate.
"Both Conservancy and the Git project are aware that the initial branch name, 'master,' is offensive to some people and we empathize with those hurt by the use of that term," said the Software Freedom Conservancy.
GitHub took action based on the Conservancy's suggestion and moved away from the term master when a Git repository is initialized, "We support and encourage projects to switch to branch names that are meaningful and inclusive, and we'll be adding features to Git to make it even easier to use a different default for new projects." As a result, GitHub renamed the master branch to main branch. (Source).