The RESTEasy project will rename its GitHub 'master' branch by this Friday (April 9, 2021). In particular, the 'master' branch will be renamed to 'main', and the `main` branch will be set as the default branch for Pull Requests. 

Any already submitted PRs targeting the 'master' branch will automatically be
redirected to the 'main' branch. For the local environment, developers should
do a fetch of the project from GitHub, and the 'main' branch will be fetched. 
And all existing work against the 'master' branch should be migrated to 'main' branch, and when you open a PR it will default to main. Here are the steps to take locally: - Do a git fetch upstream to get the 'main' branch - rebase your working branch from the main branch(to get the latest commit from upstream) - Do the Pull Request workflow as usual(push to forked repo / create Pull Request), and Github will use 'main' branch to create the Pull Request by default. 
In addition, all new PRs will by default target 'main' instead of 'master'. For more details on the Github branch renaming, here's the document for reference: - https://docs.github.com/en/github/administering-a-repository/renaming-a-b... -- Cheers, Wei Nan | JBoss