[vbat99]

Fresh day for me, so will be looking into these soon.

The items that are automatically excluded are hard-coded into Media Companion.
These include 'Recycle Bin', 'System Volume Information' just to name a few.

The reason we use a Hyphen - before the trailer.extn is to definitively separate from a Movies title and the word trailer.
I see the addon does support this

Practical scenario of how themes are picked up by TvTunes
Regardless of how they are named and the file structure you have selected to use in TvTunes (Video folder, Themes folder or Custom path), TvTunes will play all audio files, which extensions are supported by TvTunes, as long as they include the string "theme" in their names. There is an additional feature provided only by the "Themes" folder, which allow you to even ignore the string "theme" in the names.
For example, all the following audio files will be played by TvTunes as themes for Maleficient (2014) regardless of the TvTunes' file system chosen:

Maleficent (2014) 1080p BRRip H264 AAC-theme.ext
Theme - Meleficient Suite.ext
The Curse Won't Reverse theme.ext
Arthemesia.ext (this will play too ;-))
Theme.ext, theme1.ext, theme2.ext, theme3.ext, etc.

And if the themes are within the Themes folder, the following will also be played:

Would it be possible for you to test this as -theme.extn?

I only ask as this would allow less confusion (easier programming) in Media Companion.