Those are what NogDog is talking about. They are part of the Filter extension, being the different filters provided and used in the functions he linked to. To see what has changed since PHP 5.2, which is when the extension was introduced, see the relevant changelog entries in the manual (i.e., [man]filter.filters.sanitize[/man] and [man]filter.filters.validate[/man], and [man]filter.filters.flags[/man]). To see what has changed in PHP 7.0, see the same changelogs for 7.0 entries.
Not seeing the relevance of MariaDB here.