I managed to solve the problem using a filter from the bricks builder theme, as I processed the query return before reaching the front-end, but I need to know if there is any way to solve the problem only through the metabox, as the objective is to list only the classes active.
Below is the code:
https://pastebin.com/ZDcDxd0S
I would like to take this opportunity to ask where the metabox saves the data for the custom fields, because the wp_postmeta table only contains the definition of the fields, but I couldn't find the data in that table.
https://pastebin.com/hnQLZJXR
The image below shows the definition of the field that is saved in the wp_postmeta table, but I couldn't find the field data, can you clarify this question?
https://ibb.co/SvLRLB5
