Routines that can be invoked with a variable number of arguments

SELECT 
  pg_namespace.nspname AS routine_schema, 
  pg_proc.proname AS routine_name, 
   pg_get_function_identity_arguments(pg_proc.oid) AS parameters,
  regexp_replace(pg_get_functiondef(pg_proc.oid),'[\r\n]','<br>','g')  AS routine_src,
  pg_type.typname AS function_return_type,
CASE WHEN pg_proc.prokind='f' THEN 'FUNCTION'
WHEN pg_proc.prokind='p' THEN 'PROCEDURE'
WHEN pg_proc.prokind='w' THEN 'WINDOW FUNCTION' END AS routine_type,
pg_language.lanname AS language
FROM pg_catalog.pg_proc INNER JOIN pg_catalog.pg_namespace ON pg_proc.pronamespace = pg_namespace.oid
INNER JOIN pg_catalog.pg_language ON pg_proc.prolang = pg_language.oid 
LEFT JOIN pg_catalog.pg_type  ON pg_proc.prorettype = pg_type.oid
WHERE pg_proc.provariadic<>0
AND pg_proc.prokind<>'a'
AND pg_proc.proname NOT IN ('f_assume_you_must_use_files', 'f_check_format_comma_separated_list', 'f_check_password', 'f_default_value_with_no_match') 
AND pg_namespace.nspname NOT IN (SELECT schema_name
FROM INFORMATION_SCHEMA.schemata
WHERE schema_name<>'public' AND
schema_owner='postgres' AND schema_name IS NOT NULL)
AND NOT EXISTS (SELECT 1
FROM pg_catalog.pg_depend d 
WHERE EXISTS (SELECT 1 FROM pg_catalog.pg_extension e WHERE d.refobjid=e.oid) AND
d.objid=pg_proc.oid)
ORDER BY routine_schema, routine_name, parameters;