Collation for accent-insensitive comparison on Postgres?

On PG 13 documentation, there are several examples of ICU collations for specialized purposes. It is also mentioned that ICU locales exist that allow creating collations to ignore accents, and that they can be found on

However, after reading that document, I am still unclear on what is the locale I should use to create an ICU collation for accent insensitive comparisons in Spanish.

What is the name of such an ICU locale? Is there any list of ICU Spanish collations?