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 :: esc_attr()
- String The formatted string.
Applies WordPress’ esc_attr function to the field value, for formatting strings to be safely used inside HTML tag attributes.