Developed and delivered RowCounter delete-marker counting features for both the apache/hbase and HubSpot/hbase repositories, enhancing data visibility and troubleshooting capabilities for HBase users. Leveraging Java, HBase, and MapReduce, the work introduced new command-line options and updated the RowCounter tool to quantify and classify various delete marker types within HBase rows. The implementation included updates to the Mapper logic and comprehensive unit tests to validate the new functionality, ensuring reliability and accuracy. This cross-repository effort improved observability for operators and data teams, laying a foundation for more granular analytics on deletion semantics and supporting better data governance practices.