Canon patent for lubricating body cap

The Canon patent describes a body cap that keeps the lens mount of a DSLR lubricated. To be honest I can’t grab the utility of this, except that it could concern the electric contacts (keeping them clean) . Since we get this patent literature translated by a machine, I am never sure the translated words are any helpful.

• Patent Publication No. 2015-121747
  • Published 2015.7.2
  • Filing date 2013.12.25
• Canon patents
  • Mount Cap
  • The mount and abutting surface, and oil-impregnated possible member, such as a porous plastic

[via Egami]