The sqlite file format is documented and probably has the most insane backwards compatibility out there. The developers pledged to keep it backwards compatible

The sqlite file format is documented and probably has the most insane backwards compatibility out there. The developers pledged to keep it backwards compatible until 2050. In fact Library of Congress has recognised it as one of the few data formats for long term archival. https://sqlite.org/fileformat2.html https://sqlite.org/fileformat2.html https://sqlite.org/lts.html https://sqlite.org/lts.html https://sqlite.org/locrsf.html https://sqlite.org/locrsf.html