A Heritrix Crawler developer designs and implements web crawlers using the Heritrix software - an open-source, extensible, web-scale, archival-quality web crawler project. They configure the crawler to navigate websites and download data based on specific requirements, while respecting robots.txt and other access limitations. They also manage the storage and organization of the crawled data, ensuring it is accessible and usable for further analysis. Additionally, they troubleshoot any issues that arise during the crawling process, optimize the performance of the crawler, and update the crawler's settings to adapt to changing web conditions or project needs.