Azure DevOps Server, previously known as Team Foundation Server (TFS), is a self-hosted, on-premises version of Azure DevOps. It provides a set of collaborative development tools for teams to plan, track, and manage their software development projects. Azure DevOps Server is designed to help organizations that prefer to keep their development and collaboration tools within their own data centers or on-premises servers. Here are key aspects and features of Azure DevOps Server (TFS):

1. Work Item Tracking: Azure DevOps Server allows teams to create, track, and manage work items, including user stories, tasks, bugs, and features. Teams can use customizable Agile boards and backlogs to manage their work.

2. Source Code Management: Azure DevOps Server includes version control systems, supporting both Team Foundation Version Control (TFVC) and Git repositories. Developers can check in code, branch, merge, and conduct code reviews.

3. Build Automation: Teams can set up build pipelines to automate the build and deployment process. Azure DevOps Server supports continuous integration and continuous delivery (CI/CD) pipelines.

4. Test Management: Azure DevOps Server includes test management capabilities for creating and managing test cases, executing test runs, and generating test reports. It also integrates with various testing tools.

5. Package Management: Similar to Azure DevOps Services, Azure DevOps Server offers Azure Artifacts for hosting and managing packages used in software development.

6. Integration and Extensibility: Azure DevOps Server can be extended through various extensions and integrations. There is a marketplace where you can find extensions to enhance its functionality.

7. Customization: Teams can customize their Azure DevOps Server instance by defining process templates, creating custom work item types, and configuring team settings to align with their development processes.

8. Security and Access Control: Azure DevOps Server provides robust security features, including role-based access control (RBAC) to restrict access to specific areas and functionalities.

9. Reporting and Analytics: Teams can generate reports and dashboards to gain insights into their development processes and project progress. Azure DevOps Server includes built-in reporting capabilities.

10. Integration with Visual Studio and Visual Studio Code: Developers can integrate Azure DevOps Server with Visual Studio IDE and Visual Studio Code for seamless development and version control integration.

11. Migration and Upgrade: Azure DevOps Server supports migration from older TFS versions and upgrade paths to the latest version.