Thanks @hube2
That is really helpful, however, this particular statement does not quite ring true in practice for me:
“Once a field group is synced from the parent theme a copy of that group is saved in that acf-json folder in the child theme if it exists — Once this happens the field group is forever disconnected from the parent theme”
I have a multisite install with a parent theme and several child themes, all containing an acf-json folder
From a site running a child theme, syncing field groups from the parent does not put copies in the child theme acf-json folder unless an edit to one of those field groups is made from the child theme site
Even when that happens, however, there still seems to be a connection to the parent because, when such a field group is updated in the parent theme, the child theme site is given the option to sync which overrides the previous edits
That is actually good for us and our goals but I wanted to mention it in case I am missing something
