There are 3 main string types in MariaDB: CHAR, VARCHAR and TEXT. They vary storage methods, but they are using same comparision functions. MariaDB supports a lot of character sets and each character set supports many ways to comparison (for different languages and case sensetivity). Set of rules for comparing characters in a character set named collation.
Now all collations have a one common rule: ignoring trailing spaces. So strings ‘aa ‘ and ‘aa’ are equal. And the purpose of my proposal to add NO PAD collations, i. e way to take trailing spaces into account.