The name "main" is becoming the new standard because of negative associations with the name "master".
The Internet Engineering Task Force (IETF) points out that "Master-slave is an oppressive metaphor that will and should never become fully detached from history" as well as "In addition to being inappropriate and arcane, the master-slave metaphor is both technically and historically inaccurate."
Reference: https://www.tidyverse.org/blog/2021/10/renaming-default-branch/ (usethis' helper functions make the change pretty much painless)
The name "main" is becoming the new standard because of negative associations with the name "master".
Quote above from https://www.hanselman.com/blog/easily-rename-your-git-default-branch-from-master-to-main