Currently, in the /sites method, a site can have a site_state of: normal, open_beta, closed_beta, or linked_meta.
This makes it easy to tell if a main site is in beta or not. But it becomes a 2 or 3 step process to determine if a meta site is in beta -- rather than a straight table read.
For all meta sites in beta, please change the site_state to linked_meta_beta or similar.
Or add the launch_date field like normal, main sites have.
PS: I mainly care about beta sites because they are not in the Stack Exchange Data Explorer (SEDE). The problem that spawned this question could also be solved if /sites returned a value data_in_data_explorer -- set to true or false, for each site.
