A more thorough explanation:

Definition: An attester is someone who confirms or verifies something, often by providing evidence or testimony.

Examples:

• A witness in a court case is an attester who provides testimony about what they saw or heard.
• A notary public is an attester who verifies the authenticity of signatures on legal documents.
• A financial auditor is an attester who confirms the accuracy of a company's financial statements.

These examples illustrate how an attester is someone who provides assurance or validation of something. They are often relied upon to provide evidence or testimony that supports the truthfulness or accuracy of a claim or statement.