We deploy Firefox to users in our office. Generally we have usually used Public Fox Add-in to lock down Firefox so users can not install custom tools. We have also disabled check compatibility and modified disable scopes in the firefox.js which appears to be gone in this new version. It also appears the migration.js is gone which we also modify. Not to mention configuring the browserconfig.properties.

Seems like you have purposely closed up the files that will allow a company to lock down firefox. We also get rid of the private browsing feature which no does not seem possible.