A "security scheme" in JIRA is used to manage Issue permissions and access controls. These schemes allow administrators to control who can view, edit, and perform various actions on issues within a project. By configuring security schemes, organizations can ensure that sensitive information is protected and access is restricted as needed. Thus, option 2 is correct.

To create a filter subscription in JIRA, you need to navigate to the Filters menu, select the desired filter, and then click on "Subscribe." From there, you can configure the frequency and recipients for email updates based on the filter results.

The correct option is that the Atlassian Marketplace is a platform for finding and installing JIRA plugins and add-ons developed by Atlassian. It serves as a central hub where users can browse, purchase, and download various plugins and add-ons to enhance the functionality of their JIRA instance.

Verifying the integrity of a JIRA backup file is essential to ensure its reliability before performing a restore operation. One method to verify integrity is to perform a test restore in a separate environment to confirm that the backup can be successfully restored without errors. Additionally, comparing checksums or file sizes between the original and backup files can help detect any discrepancies that may indicate corruption. Checking file permissions and renaming the file can also be part of the verification process to ensure proper access and identification of the backup file.

Well-defined naming conventions improve collaboration within a project team by enhancing clarity and understanding of issues. Consistent naming conventions provide a common language for team members, reducing ambiguity and ensuring everyone is on the same page. This fosters effective communication and collaboration, leading to better project outcomes.

The "Delete All Comments" permission in JIRA controls the ability to delete comments. This permission, when granted to a user or role, allows them to delete all comments associated with an issue. It's crucial for managing discussions and maintaining the relevance of comments within the issue history.

Transition conditions define the rules that must be met for a transition to occur in a workflow. By customizing transition conditions, you can ensure that a code change cannot move to the "Approved" status without passing a code review.

In JIRA, users can select multiple issues for performing Bulk Operations using the issue navigator. This feature allows users to search for and filter issues based on various criteria, and then select multiple issues from the search results to perform actions on them in bulk.

Permission schemes in JIRA are utilized to define access rights for projects. They allow administrators to specify who can view, create, edit, and transition issues within a project. By configuring permission schemes, organizations can ensure that users have appropriate levels of access to project resources, maintaining security and data integrity.

JIRA gadgets can be configured to display information from specific JIRA filters. Filters allow users to define and save specific criteria for selecting issues, making it easier to display relevant data on dashboards and gadgets.