Oracle Database 26ai is now availble. If you haven't you downloaded already: Why?
Purpose
According to the Oracle Text Reference online doc the CTX_ANL PL/SQL package
is used with AUTO_LEXER and provides procedures for adding and dropping a custom dictionary from the lexer.
A custom dictionary might be one that you develop for a special field of study or for your industry.
In most cases, the dictionaries supplied with Oracle Text are more than sufficient to handle your requirements.