When adding custom UI elements to a Jenkins plugin, the development should focus on HTML and JavaScript. These technologies enable the creation of interactive and user-friendly interfaces within the Jenkins environment.

The 'stages' section in a Jenkinsfile is used to define the stages of a pipeline. Each stage represents a phase in your build process, and within each stage, you can define multiple steps.

Declarative pipelines in Jenkins are designed for simplicity and readability. They provide a structured and concise syntax, making it easier to define and understand complex pipelines.

The Plugin Manager page in Jenkins is where users can view and manage all installed plugins, including their versions and statuses. It's a crucial part of maintaining and updating Jenkins functionality.

Jenkins can be integrated with LDAP (Lightweight Directory Access Protocol) for role-based access control. LDAP integration enables the use of existing user accounts and groups for managing access to Jenkins resources.

The best practice involves using Shared Libraries to modularize and reuse parts of job definitions. Shared Libraries allow you to define common functionality and use it across multiple projects.

Jenkins can automatically poll source control systems like Git to detect changes in the source code. This enables Jenkins to trigger builds when changes are pushed to the repository.

The Node Management plugin is vital for managing and scaling Jenkins nodes in a distributed setup. It allows administrators to add, remove, and monitor nodes, ensuring efficient resource utilization.

In a parameterized build, the "Array" parameter type is used for accepting multiple string inputs. This allows users to input a list of values during the build process.

A Jenkinsfile is primarily used for defining the pipeline as code. It allows you to describe the entire build process, including stages, steps, and conditions, in a script format that can be versioned along with your code.