One of the accessibility tools reported the following when inspecting https://download.java.net/java/early_access/jdk15/docs/api/

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Description

Landmarks must have a unique role or role/label/title (i.e. accessible name) combination

Fix any of the following

The landmark must have a unique aria-label, aria-labelledby, or title to make landmarks distinguishable

Failure

Moderate: Ensures landmarks are unique

HTML

<nav role="navigation">

Selector

header > nav