Index Mobile and its removal

I had a look in the contents of the WP-Super-Cache and i am seeing this files:
http://www.domain.com/title-of-my-post/index-mobile.html
http://www.domain.com/title-of-my-post/index-mobile.html.gz
Obviously these links do not exist and give 404 errors.
Questions.

1) What is index-mobile.html and index.mobile.html.gz
2) Why are they appended to the end of some random posts?
3) Surely the Rejected User agents should have prevented these requests from bots?

One another issue would be the removing of the cache, seems not to react when I manualy remove it.

http://wordpress.org/extend/plugins/wp-super-cache/

http://wordpress.org/plugins/wp-super-cache/