This document discusses Project Haystack, an open-source standard for tagging IoT device data to make it easier to analyze and use across applications. Project Haystack provides a universal markup language to capture device data semantics and make the data self-describing. It aims to address the challenge of integrating data from diverse equipment systems by creating a standardized approach to defining information models. The document outlines how Project Haystack works, its adoption in the industry, and resources for learning more.