Thane, guess what?
I've never seen the alternate method used for real, but while testing WiFi adapters on TC-8 this occured
 Acquiring latest version.. 
 Version not found, 
 attempting alternate method..
 The Latest version is 53.0 
 
--2017-04-25 05:20:34--  http://download.cdn.mozilla.net/pub/mozilla.org/firefox/releases/53.0/linux-i686/en-US/firefox-53.0.tar.bz2
Resolving download.cdn.mozilla.net (download.cdn.mozilla.net)... 23.215.100.138, 23.215.100.147, 2600:1406:28::b833:f8, ...
Connecting to download.cdn.mozilla.net (download.cdn.mozilla.net)|23.215.100.138|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 60504818 (58M) [application/x-tar]
Saving to: '/tmp/firefox.tar.bz2'
/tmp/firefox.tar.bz2                     100%[================================================================================>]  57.70M  3.23MB/s    in 18s     
2017-04-25 05:20:52 (3.22 MB/s) - '/tmp/firefox.tar.bz2' saved [60504818/60504818]
Looking into this further...