https://docs.sonarqube.org/display/PLUG/Plugin+Library links to https://docs.sonarqube.org/display/SONARQUBE67/LDAP+Plugin for the LDAP plugin but that page says in red that this is an old archived version of the docs. Maybe it would make sense to update the link to the current page if there is on or create one if not.
You’ll find the most recent documentation for the LDAP plugin in our documentation on Delegated Authentcation.
Technically documents related to versions of SonarQube that aren’t the latest (right now, v7.6) are considered archived, including those for our LTS. Since the LDAP plugin now has documentation embedded in the platform documentation, the old LDAP plugin docs are archived (but still relevant for SonarQube v6.7)