Installation of Firefox from Alpine Edge

For people who are stumbling upon this question, the 1 line answer is

apk --no-cache add --repository http://dl-cdn.alpinelinux.org/alpine/edge/testing firefox

This will create a single 1-time install of firefox using the test repo of the edge branch.

In order to figure out the right link, navigate to the APK package mirror. and put in a search for Firefox. The branch and repository will be populated and your dockerfiles can be updated accordingly.

Editing of the /etc/apk/repositories file will also achieve the same effect.