TEXT[(M)] [CHARACTER SET charset_name] [COLLATE collation_name]

A TEXT column with a maximum length of 65,535 (216 - 1) characters. The
effective maximum length is less if the value contains multi-byte
characters. Each TEXT value is stored using a 2-byte length prefix that
indicates the number of bytes in the value.

An optional length M can be given for this type. If this is done, MySQL
creates the column as the smallest TEXT type large enough to hold
values M characters long.

URL: https://mariadb.com/kb/en/text/

