JQL, or JIRA Query Language, is a robust querying language provided by JIRA for searching and retrieving specific sets of issues based on various criteria, facilitating efficient issue tracking.

In JIRA, you can add various gadgets to your dashboard to provide visual representations of data, such as charts, graphs, and statistics. These gadgets are customizable and offer insight into project progress or team performance.

In JIRA, you can grant a user the ability to create issues in a project without giving them full project admin access by adding them to the "Create Issues" permission scheme in the project settings. This allows users to create new issues within the project without granting them full administrative privileges.

In JIRA, project administrators have the ability to define custom fields within their project. These custom fields can be tailored to capture specific information relevant to the project's requirements, such as priority, due date, or any other custom data.

In JIRA, a scheme defines which screens and issue types a custom field is available for. This allows for customization based on project requirements, ensuring that custom fields are accessible where needed. Therefore, the correct option is "Scheme."

Comprehensive documentation provides clear instructions and guidelines for backup and restore procedures. It includes detailed steps, configurations, and considerations, ensuring that administrators can efficiently execute the restore process without ambiguity. Comprehensive documentation minimizes the risk of errors and enhances the reliability of the restore operation.

A "post function" in a JIRA workflow is a task or action that is executed after an issue transitions from one status to another. These functions are typically used to automate actions such as updating fields, sending notifications, or triggering external processes. They are executed after the transition occurs.

Before upgrading a critical JIRA plugin, it is essential to ensure a smooth transition. First, backup the JIRA instance to avoid data loss in case of unexpected issues. Then, test the new plugin version thoroughly in a sandbox environment to identify any compatibility issues or unexpected behavior. Only after successful testing should you proceed with upgrading the plugin in the production environment.

In the context of JIRA, "scaling" primarily refers to handling a growing number of users and projects. This includes ensuring that the system can accommodate increased data volume, user interactions, and project complexity effectively.

JIRA plugins and add-ons can indeed be used to extend JIRA's functionality by adding new features and capabilities, such as integrations, automation, or enhanced user interface elements.

Create a new user account and assign permissions accordingly: When a new team member joins, you should create a new user account in JIRA and assign the necessary permissions based on their role and responsibilities. This ensures that the new member has access to the relevant features and projects within JIRA, facilitating their integration into the team and workflow.

Agile Reports are the most suitable for enhancing reporting capabilities in JIRA. They offer comprehensive insights into project progress, sprint performance, and team productivity. You can find them in the JIRA Marketplace, where numerous plugins and add-ons are available to extend JIRA's functionality. These reports help visualize data and facilitate informed decision-making.