Exposing a type of field operation (flag lists) for search index view I installed the flag list operations module which gives me the ability to do operations on my views results. But this flag list operations doesn't show up on my search index view as seen below. 

I'm sure there is some parameter or variable that is set in the flag list module that is preventing this operation to show up on the search index view. 

What should I be looking for in the flag list module code to enable this operation to show up in the search index view?
Those flag list operations come from a Views handler; they're applied only to the node entity type in flag_lists_views_data_alter.

The Indexed node isn't a node entity, it's something specific to the search API module (added in search_api_views_views_data). It only contains fields that are indexed, plus any extra stuff search API or contrib modules add on.

I haven't tried it, but you may be able to include the nid in the index, and add a relationship in the View to Content. That would, in theory, give you access to everything that Views knows about for a node.

Failing that, you'll probably have to implement your own Views handler, implement hook_views_data_alter, and find the table whose field handler you need to override (it'll be search_api_index_MACHINE_NAME). The class in includes/flag_lists_handler_field_ops.inc would probably be a good template to start from.