This port will be removed on 2020-12-31 if not fixed
lang/spidermonkey60's only reason of existence was an older polkit version.
The new polkit 0.118 depends on a python3 using spidermonkey.
So I don't see any reason to invest time in making it work in a python3 world.
A commit references this bug:
Date: Thu Sep 24 19:35:08 UTC 2020
New revision: 549944
lang/spidermonkey60: mark deprecated (uses python2 to build)
This port was added for a past polkit update.
Newer spidermonkey version can be built with python3 and should be prefered.
Reported by: swills