Masterpress 1.3.6 is a compatibility release. It resolves an edge case with shared fieldsets not working for MySQL 8 when the fieldset is limited to more than 1 post type or taxonomy or excluding any post types or taxonomies.
MPFT_RelatedTaxonomy :: taxonomies()
Retrieves a collection of the taxonomies selected in the field UI.
Note: you can further clarify the selected taxonomies by setting the args parameter to a wp_parse_args compatible array or string.