In JIRA, you can see that user details are formatted with the full name and a link to the user's profile within the application. For example, when the issues are displayed in the issue navigator, the assignee and reporter are displayed as follows:
You can see that the link points to the profile page.
But what if we want to change how user details are displayed? Say, we want to display the user's avatar alongside their name, or that we want to display their usernames with an external link, such as a link to the user's Twitter profile.
JIRA provides the User Format plugin module to serve this purpose. Using this module, we can define different formats in which the user will be displayed, and we can use them within the existing JIRA display or within our custom plugins.