DVD with .layout and .LAY files

[Case]

What is the use of files "TITLE.layout" and "VOB_DATA.LAY" in a VIDEO_TS folder?
Are they perhaps leftovers from a (DVD Studio Pro?) authoring process?
Can I discard them when burning? Is there any use in keeping them?

I downloaded this free DVD that came with these files. I don't think I've seen them before in a VIDEO_TS folder. Just wondering what they are for.

[Herve]

What is the use of files "TITLE.layout" and "VOB_DATA.LAY" in a VIDEO_TS folder?

no one

Are they perhaps leftovers from a authoring process?

yes

Can I discard them when burning? Is there any use in keeping them?

do what you want, discard or not (no dvd-player will try to access to these files)

PS: there is only few usefull files in a DVD-VIDEO
on its root level, the VIDEO_TS and AUDIO_TS are the only ones necessary files/folder (JACKET_TS is optionnal)
so, if you put another file/folder on the root level, the DVD-Player will just ignore it (aka, you can put anything you want in the root level without side effects, personnally I put a "ROM" folder when I have some data to store in my DVD-VIDEO )

bye