Is it possible to hook into and change the HTML markup of how fields are rendered in the back-end?
More specifically, I would like to prepend the “Toggle All” option in a checkbox field in a separate HTML tag and not have it be part of the list containing the regular choices. I know, this could always be done by brute Javascript force but I was hoping for a less heavy-handed solution? Thanks in advance!
No, it is not possible to alter how ACF renders the fields.
Thanks for clearing that up. In the meanwhile, I managed to achieve the visual result I was aiming for using the CSS column-count and column-span properties.