We'll need to find and reference the policy documentation once this becomes available. Despite the minimum "78" version, I don't expect the policy to have a negative effect on other versions, so it should be able to be coupled with the policies.json techniques we're already using.
Similar to #526, Firefox 78 will soon be adding the ability to whitelist protocol handlers. Quoting a Firefox developer:
We'll need to find and reference the policy documentation once this becomes available. Despite the minimum "78" version, I don't expect the policy to have a negative effect on other versions, so it should be able to be coupled with the
policies.json
techniques we're already using.The (closed) bug report which requested this feature is here: https://github.com/mozilla/policy-templates/issues/532. That repo will ultimately contain the examples needed to leverage this feature.