Firefox 60 will feature a new component named Policy Engine that will provide GPO support on Windows, allowing system administrators to control Firefox instances deployed across an internal network. Work on this feature has been progressing according to plan, and its launch is still scheduled for Firefox 60 — Firefox ESR 60 version, as well.Is it possible to enforce local GPO over the domain?
Yes, you can set the policies in a Domain GPO and make it enforced. Then use GPO masking - add all the servers in question to a group & only allow that group read access to the new GPO. This assumes they are all Computer settings, if you need User settings to get applied you may want to look at using a loopback.What is a group policy template?
The Group Policy template is a folder structure within the file system that stores Administrative Template-based policies, security settings, script files, and information regarding applications that are available for Group Policy Software Installation.