In the Patrons chapter, under Notices (https://koha-community.org/manual/latest/en/html/patrons.html#notices) there is an internal reference to the patron's messaging preferences. This reference is not formatted correctly and doesn't lead anywhere. Current The `patron's messaging preferences <#setpatronmessaging>`__ are set There is unfortunately no specific section to setting patron messaging preferences, it is described in Adding a patron. The reference should be removed or a section should be added and the reference properly formatted.