Purpose of foam pad on top of rectifier

[dreamr]

Why is it there? Although my bike runs fine, the foam around the top of the rectifier has mostly disintegrated. In fact, part of it looks like it may have gotten very hot at some time. I haven't noticed any odd odor when it runs or idles.
Any thoughts about what I should do about this, if anything? Thanks for any comments.

[kloan]

Foam? Mine doesn't have any.... probably be fine without it is my guess.