I don't think this should get moved to their adapters. It is context-specific, but it has to do with what terms the site detects and treats specially, and then what source-specific filters this becomes. For example, you might search speeches for a federal bill ID, or GAO reports for a US Code citation, etc.

Rather, I think this should be part of a separate system about special handling of search terms. Maybe sitting inside `subscriptions`, but not inside `adapter`.