Domain Mapping System allows to map domains to WP pages and/or custom types.
I have no idea, WordPress 3.3.2 - 3.4.2 surely are.
Please report it on github.
Possibly, yes. That's because I use the php function
parse_str() . It turns . (dot)
into _ (underscore), so they are manually replaced afterwards. If it actually bothers
you, I will change this.