@duckAsteroid kindly pointed to http://www.qudt.org/2.1/catalog/qudt-catalog.html. The latest version of QUDT, a Unit and Quantity Ontology catalog affiliated with W3C that was developed by NASA, the board of directors also includes a representative of Siemens. Given the UCUM development seems to have stalled since 2017 this could be an alternative.
@duckAsteroid kindly pointed to http://www.qudt.org/2.1/catalog/qudt-catalog.html. The latest version of QUDT, a Unit and Quantity Ontology catalog affiliated with W3C that was developed by NASA, the board of directors also includes a representative of Siemens. Given the UCUM development seems to have stalled since 2017 this could be an alternative.