https://docs.typo3.org/m/typo3/docs-how-to-document/main/en-us/GeneralConventions/FileStructure.html#includes-rst-txt

Introduction

What does it do?

With yellowpages2 you can build your own little industry directory for your TYPO3 website. It comes with a list and a configurable detail view. Above the list view we implemented an A-Z navigation to jump directly to industry directory entries which will start with clicked starting letter.