Function std_search_priority 

pub fn std_search_priority(objtype: &str) -> i32

ObjType(..., searchprio=...) for the std domain’s types (domains/std/__init__.py:725-734). ObjType defaults searchprio to 1 (domains/__init__.py:53), so every type the table does not mark unsearchable — confval, envvar, cmdoption, and whatever add_object_type registers — is 1.