What are some common misunderstandings or confusion surrounding the term "header" in the context of web development?

One common misunderstanding is the confusion between the <header> HTML element and HTTP headers. The <header> element is used to define a header for a document or section, while HTTP headers are used to pass additional information between the client and server. To avoid confusion, it's important to understand the context in which "header" is being used in web development.

// Set a custom HTTP header in PHP
header('Content-Type: application/json');