Critical Security BugFix:
The HTTP response header lines are in the usual text header format, which is: one line per header, of the form "Header-Name: value", ending with CRLF.
SafeSquid failed to correctly parse headers when the number of spaces or tabs between the ":" and the value was more than one.
One of the immediate mal-effects of this was non-detection of "Transfer-Encoding: chunked" headers.
This was largely witnessed with Microsoft IIS/6.0 webservers.