Version 18.4.0 of the driver adds support for the UTF-8 client encoding (enabled with the "Use Unicode UTF-8 for worldwide language support" checkbox under Region Settings in Windows 10). Note ...

When inserting data from UTF-8 enabled clients, the driver translates UTF-8 encoded strings to the database collation code page before sending it to the server.

The core function of this syntax is to inform the database that the string should be processed using Unicode encoding (such as UTF-16), primarily for matching fields of Unicode types like NVARCHAR.