where does backdrop store vocabularies?

i cannot seem to find an answer to this through searching.

i see that the database structure created by the installation does create a few taxonomy tables, one of which is taxonomy_vocabulary, which is where drupal 7 stored vocabulary definitions, with a vid primary key.

i created a new vocabulary using the admin ui, and the taxonomy_vocabulary table remains empty. yet i can load it using taxonomy_get_vocabularies(). 

where is the new vocabulary stored? and is the taxonomy_vocabulary table now completely unused?

thanks to anyone who can clarify this for me, or point me at some actual documentation that describes this.