Per the README
https://ftp.mozilla.org/pub/firefox/releases/latest-esr/README.txt
the most recent version of firefox should download from the following link
"https://download.mozilla.org/?product=firefox-esr-latest&os=osx&lang=en-US"
(I'm using firefox-esr-install.py)
However, the link is still downloading 52.8
Did I miss something or has mozilla just not updated the link?
Try this page.
https://www.mozilla.org/en-US/firefox/organizations/all/
Note the tab near the top-right.
Until version 60.2.0 Firefox 60 is in "qualifying" status for ESR and 52 is still active. The path to Firefox 60 ESR is "60.0esr" as seen here:
http://download-origin.cdn.mozilla.net/pub/firefox/releases/
Ref: 
I found when I was using a curl command for "https://download.mozilla.org/?product=firefox-esr-latest&os=osx&lang=en-US" that I had to use the follow link argument to resolve downloading the correct installer.
FWIW, Firefox 52 only supports macOS 10.9 - 10.12; Firefox 60 supports macOS 10.9 - 10.13...
Firefox 52.0esr System Requirements
Firefox 60.0esr System Requirements
Plug-ins will probably not be ready...and you can't roll back your profile...but...varoom!!
I switched away from that version of the Script
I am now using this bash version
https://www.jamf.com/jamf-nation/discussions/26076/mozilla-firefox-esr-update-script
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