Traceroute Won't Draw Your HTTP Proxy Chain
Use traceroute for its IP-level path question without treating its hops as an inventory of application proxies.
A traceroute to an external address does not consult your browser's HTTP proxy settings. It traces the IP-level behavior of its own probes.
An explicit forward proxy accepts the application's connection and creates an onward connection. The browser-to-proxy path and proxy-to-destination path are therefore separate from an ordinary probe sent directly toward the destination.
You cannot count the displayed routers and conclude that no HTTP proxy exists because there is no extra unfamiliar hop. Missing replies, tunnels, filtering, and a different probe protocol limit that inference further.
Use traceroute for the path question it actually asks. To establish an application's proxy route, inspect its effective proxy choice and connection exchange, then correlate with the intended intermediary's records where available.
An observed exit address identifies another useful boundary, but still does not list every intermediary. A proxy chain is an application-level arrangement; TTL-limited probes are not a universal way to reconstruct it.