Sigh.
Ive been waiting years to push our Kazoo to production waiting for 5.0 and the app exchange(Seriously, I think I started the evaluation of Kazoo around 2020). But Zack you are wrong here. The MPL requires distribution of the software have source code also released, but Kazoo has not distributed anything publicly of 5, so there is no need for code to be distributed yet. Your interpretation of the license would require you to push every edit, revision, commit, keystroke, etc to be made public.
The only people who could possibly have a case for arguing for access to the source code would be people who have paid for Global Infrastructure, which given how much it costs, they probably do have access to the code.
What would really be helpful though, other than even a rough quater or even year estimate for release of 5, is an understanding of the upgrade from 4.3 to 5. How much effort will the upgrade be? Should we just push 4.3 into prod because the process to upgrade to 5.x will take only a few hours? Or is it better to wait a few more months and deploy straight to 5?