If I right-click a playlist and export it with the settings in the attached (export.jpg) screenshot, it produces the following playlist:
<?wpl version="1.0"?>
<smil>
<head>
<title>Test Playlist</title>
</head>
<body>
<seq>
<media src="Music\Rock\Nickelback\Here And Now\Nickelback - Here And Now - 2 - Bottoms Up.wma"/>
<media src="Music\Rock\Van Halen\1984\Van Halen - 1984 - 05 - Drop Dead Legs.wma"/>
</seq>
</body>
</smil>
This is good and it works in my 2014 Mazda6 that supports WPL playlists. (Music and playlist is on a USB drive.)
On the other hand, if I find my USB drive under Drives and Devices and sync it, using the settings in the attached (sync.jpg) screenshot, it produces the following syntax which does NOT work in my car as it does not seem to be a WPL formatted playlist.
<ASX VERSION="3.0"><TITLE>Test Playlist</TITLE>
<ENTRY><REF HREF="Music\Rock\Nickelback\Here And Now\Nickelback - Here And Now - 2 - Bottoms Up.wma" /></ENTRY>
<ENTRY><REF HREF="Music\Rock\Van Halen\1984\Van Halen - 1984 - 05 - Drop Dead Legs.wma" /></ENTRY>
</ASX>