Lip at the end of the floor pan

[nicka]

Working on a '71 Barracuda.  The floor is in.  Working on the footwells.  I noticed this lip at the end of the floor.  What's the purpose of this lip?  Looks like a great candidate to store road debris.

[nicka]

Reviewing a restored vehicle I do see the two lips behind the main floor pan support but can't tell if they are flat against the footwell or open?

http://www.amcri1.com/1971-plymouth-hemi-cuda/#group-36