Idea Summary
Add  apex_plugin_util.is_component_used to the API documentation and make the p_authorization_scheme_id default null. The package is already in the API document but this function is not. Also, please consider the bonus at the bottom.

It might also be interesting to expose wwv_flow_conditions as a public APEX API. It would be super easy to do:

create public synonym apex_conditions for wwv_flow_conditions
/
grant execute on wwv_flow_conditions to public
/

Use Case
So many!!

I want to check if the user preference ‘MY_FAVORITE_COLOR’ is BLUE

if apex_plugin_util.is_component_used (…'USER_PREF_IN_COND_IN_COND2','MY_FAVORITE_COLOR','BLUE'…) then …

I want to check if an item value is in a list

if apex_plugin_util.is_component_used (…'VAL_OF_ITEM_IN_CONDITION_IN_COLON_DELIMITED_LIST','P1_COLORS','BLUE:RED:GREEN'…) then …

Preferred Solution (Optional)
Put apex_plugin_util.is_component_used  into the APEX API documentation.

BONUS:

Add a few more conditions types that allow you to just check conditions of p_condition instead of an item. For example

apex_plugin_util.is_component_used ('VAL_CONDITION1_IN_COLON_DELIMITED_LIST','BLUE','BLUE:RED:GREEN')