FHS: what is "the map installer"?

In the Filesystem Hierarchy Standard 3.0 under the section *3.5.1 "The Root Filesystem - /boot : Static files of the boot loader - Purpose"*: >This directory contains everything required for the boot process except configuration files not needed at boot time and the map installer. What is this **map installer**. I wasn't able to find anything myself, hence the question. Here's the link to the document I'm referring to, just in case: https://refspecs.linuxfoundation.org/FHS_3.0/fhs-3.0.pdf