What are these queries used for?

Question

I'm using sqlx for the first times these days.

I just found out those queries executed from sqlx in my app, but I don't know what they are used for.

Can you help me understand?

SELECT
  typname,
  typtype,
  typcategory,
  typrelid,
  typelem,
  typbasetype
FROM
  pg_catalog.pg_type
WHERE
  oid = $1

and

SELECT
  attname,
  atttypid
FROM
  pg_catalog.pg_attribute
WHERE
  attrelid = $1
  AND NOT attisdropped
  AND attnum > 0
ORDER BY
  attnum