Spidermonkey jsshell binaries (just 45.8.0esr)
eg for linux-x86_64:
$ cd linux-x86_64/
$ gpg --verify firefox-45.8.0esr.checksums.asc
gpg: Signature made Thu Mar 2 03:40:50 2017 UTC using RSA key ID 5E9905DB
gpg: Good signature from "Mozilla Software Releases <release@mozilla.com>"
gpg: Note: This key has expired!
Primary key fingerprint: 14F2 6682 D091 6CDD 81E3 7B6D 61B7 B526 D98F 0353
Subkey fingerprint: F2EF 4E6E 6AE7 5B95 F11F 1EB5 1C69 C4E5 5E99 05DB
$ sha512sum jsshell-linux-x86_64.zip
a62c6fa15e46de1099b989ea664356cedfe47042f98dec62c0f302a59039f075ca1347089a5eec0961c38bdedc06625fcae96f5394833c2a7926c0980f45ad47 jsshell-linux-x86_64.zip
$ grep a62c6fa15e46de1099b989ea664356cedfe47042f98dec62c0f302a59039f075ca1347089a5eec0961c38bdedc06625fcae96f5394833c2a7926c0980f45ad47 firefox-45.8.0esr.checksums
a62c6fa15e46de1099b989ea664356cedfe47042f98dec62c0f302a59039f075ca1347089a5eec0961c38bdedc06625fcae96f5394833c2a7926c0980f45ad47 sha512 7032567 jsshell-linux-x86_64.zip
If gpg errors out saying it doesn't have the key you will have to get the key:
$ gpg --recv-key F2EF4E6E6AE75B95F11F1EB51C69C4E55E9905DB
If for whatever reason that command fails you can also get the key from:
https://archive.mozilla.org/pub/firefox/releases/45.8.0esr/KEY
Simply extract with unzip (or whatever your platform uses to extract zip files).
To run on Linux you will need to set your LD_LIBRARY_PATH
export LD_LIBRARY_PATH=${PWD}
and then just run ./js
On windows you just run js.exe