The "Project Key" in JIRA is a unique identifier assigned to each project, used in issue keys and project URLs. It is important because it helps in differentiating between projects, allowing for easier navigation and referencing within JIRA.

Issue naming conventions play a crucial role in reporting and tracking progress by facilitating categorization. Consistently formatted names enable users to quickly identify the type, priority, and status of an issue, making it easier to generate accurate reports and monitor project progress effectively.

To automatically transition issues to the "In Progress" status when assigned to a team member, you would configure an automation rule triggered by Issue Transition. This rule would initiate the transition whenever an issue moves from unassigned to assigned status.

The correct option is Option 4: Sprint Burndown. A burndown chart displays the amount of work remaining in a sprint. It is an essential tool for Agile teams to track their progress and ensure they are on track to meet their sprint goals.

The JIRA database stores all the issue data used by the application, including details about projects, workflows, users, and their activities.

When integrating JIRA with external tools, it's important to define clear processes and workflows. This ensures smooth communication and collaboration between JIRA and other tools, leading to better project management and efficiency.

Issue Security Scheme in JIRA is used to control visibility, allowing administrators to specify who can view particular issues based on their role or group membership, ensuring sensitive information remains protected.

To install a JIRA plugin or add-on, users typically navigate to the "Plugins" section of their JIRA instance. This section allows users to manage and install plugins, extending the functionality of their JIRA instance according to their specific needs.

"Gadgets" on a JIRA dashboard refer to the various visual elements or widgets that display specific information or metrics related to projects, teams, or issues. These gadgets can include charts, graphs, statistics, or lists, providing users with real-time insights into project status, progress, and performance. Gadgets are useful for reporting as they enable users to customize their dashboards with relevant metrics and data visualizations, making it easier to track key performance indicators, identify trends, and communicate project status to stakeholders effectively. By configuring gadgets on their dashboards, users can create personalized reporting tools tailored to their specific needs and preferences.

In JIRA, sub-tasks are created under parent issues, which can be either epics, stories, bugs, or other issue types depending on your project's configuration. The parent issue defines the context for the sub-task.