As of 2018, CiviCRM uses three different systems for tracking and managing issues (aka tickets) - GitLab, GitHub and Jira. This page offers a brief summary of the systems and helps developers understand when and how to use them.
As of 2019, CiviCRM uses two different systems for tracking and managing issues (aka tickets) - GitLab and GitHub. Until early 2018, Jira was also used. This page offers a brief summary of the systems and helps developers understand when and how to use them.