I collaborated for several years with Hajo on the open source library software project VuFind®, though I confess that I knew little of his life outside of our work together. I was aware of his long illness, which he faced with courage and pragmatism, but I only recently learned of his passing. Hajo contributed code to VuFind® on more than twenty occasions, including at least one new feature that has become widely used both at my institution and in the project's test suite. His code is running frequently all over the world, helping people find information that they need for their research, and I expect that this will continue for years to come. Hajo was also a founding member of the VuFind® Project Management Committee, where he served from 2021 to 2024. This group formalized the project's governance structure and documentation, helping to ensure that the work could outlast its current set of maintainers. His work in these areas also created something lasting, substantially contributing to the project’s sustainability. I never had an opportunity to meet Hajo outside of online video calls, and I knew nothing of his life outside the project (though it seems to have been a rich and eventful one). However, I always appreciated his calm and friendly presence, and I’m sorry that I didn’t have the opportunity to know him better. My deep condolences to all who knew him; it is a sad loss, but I also deeply appreciate the fact that it seems wherever he went, he left lasting legacies behind.