The "auto-hyperlink" setting:

If non-zero, enable hyperlinks on web pages even for users that lack the "h" privilege as long as the UserAgent string in the HTTP request (The HTTP_USER_AGENT cgi variable) looks like it comes from a human and not a robot. Details depend on the value of the setting.

Off: No adjustments are made to the 'h' privilege based on the user agent.

UserAgent and Javascript: The the href= values of hyperlinks initially point to /honeypot and are changed to point to the correct target by javascript that runs after the page loads. The auto-hyperlink-delay and auto-hyperlink-mouseover settings influence that javascript.

UserAgent only: If the HTTP_USER_AGENT looks human then generate hyperlinks, otherwise do not.

Better robot exclusion is obtained when this setting is 1 versus 2. However, a value of 1 causes the visited/unvisited colors of hyperlinks to stop working on Safari-derived web browsers. When this setting is 2, the hyperlinks work better on Safari, but more robots are able to sneak in.