In ACF 4 the field groups are save as a post in the post table with a post type of “acf”. This hold the record of the field group. The fields and other settings for the field group live in the postmeta table and you’ll find everything for the field group by looking for the post_id of the acf post. Most of the data is stored as serialized arrays, so be careful editing them.
In ACF 5, there are two post types “acf-field-group” and “acf-field”. the acf-field post type are child posts of the acf-field-group post type. First you need to find the parent group ID and then search for acf-field posts with that parent id. The group and field information are both saved in the post table post_content column as serialized arrays, again, be careful editing this.
