You can clone with
HTTPS or Subversion.
In the default highlight engine, the line-numbers are linkable,
with HTML anchors.
I would like to see this behavior restored when I use redmine_ultraviolet.
Unfortunately, Ultraviolet would have to be modified for this to work, since it's generating the line numbers.
Another possibility is to modify the HTML after it's been output from Ultraviolet. (Maybe with a regular expression, or nokogiri.)
Would you like to take a stab at one of those? :)