We have stopped uploading specific releases. SpiderMonkey source packages are
not an official Mozilla product, though we do try to keep them working.
https://github.com/mozilla-spidermonkey/spidermonkey-embedding-examples is the
best source of information for these releases, though you will also want to
visit the main SpiderMonkey documentation page at https://spidermonkey.dev/

The easiest way to fetch the version corresponding to the current Firefox
release is to visit the treeherder page for the release repository and click on
the first SM(pkg) link you see. That will open a small window in the bottom
left with a line like

  artifact uploaded: mozjs-86.0.1.tar.xz

where the 'mozjs-*.tar.xz' part will be a link to the actual file.

For the SpiderMonkey package corresponding to the current Firefox release:

  https://treeherder.mozilla.org/#/jobs?repo=mozilla-release&filter-searchStr=spidermonkey-sm-package

For the SpiderMonkey package corresponding to the latest ESR (Extended Support
Release), select "Repos" from the above page and choose the latest
"mozilla-esrNN" repository, then follow the instructions above. For example,
for esr78 that would take you to:

  https://treeherder.mozilla.org/jobs?repo=mozilla-esr78&filter-searchStr=spidermonkey-sm-package

Build instructions are in a toplevel INSTALL file.

To contact us via various mechanisms (realtime chat, forum, mailing list, etc.)
see the "Where to find us" section at https://spidermonkey.dev/