How to check if Oracle Database is using EBR ( EDITION-BASED REDEFINITION) or not

Question

As per Oracle's documentation, since version 11g, Edition Based Redefinition (EBR) is initialized with a default edition named ORA$BASE. Any future EBRs are children of this so-called "edition".

I've checked the documentation, but it doesn't say how to check if a database has been "edition enabled" or not, or whether EBR is in use.

Edition-Based Redefinition Technical Deep Dive (Oracle | PDF)

Is EBR in use if the following query below shows more than ORA$BASE as the existing edition or not necessarily?

SELECT * FROM dba_editions;