What is the information_schema database in phpMyAdmin or in MySQL?
Information_schema is a database that is created automatically, it contains various information used by MySQL itself.
From the MySQL 8 documentation:
INFORMATION_SCHEMA provides access to database metadata, information about the MySQL server such as the name of a database or table, the data type of a column, or access privileges. Other terms that are sometimes used for this information are data dictionary and system catalog.