Google PlayStore changed the policy for developers being able to download and install software from any location other than the PlayStore.
This is intended to protect the Android user from malicious software and is a understandable step to promote security.
I<code> Go originally downloaded and helped to install the open source SL4A, Python4Android, and JRuby4Android. This policy change no longer allows ICG to do so. You will have to install these open source apps on your own.
SL4A:
https://github.com/kuri65536/sl4a/releases
Python4Android:
https://github.com/kuri65536/python-for-android/releases
JRuby4Android:
Available within the SL4A app.