Frame mounts on down tube?

[one piece crank]

What can these forward-facing downtube mounts be used for?

 

[Patrick]

guess: mud guard?

 

[Magic]

They hold the bike together. Do not remove.

 

[Karate Monkey]

Attach googly eyes.

 

[snashters]

I think my fatboy frame came with some rubber pads to attach there to protect in case of impact with fork crown (if running a suspension fork).