policies.json

{
  "policies": {
    "DisableAppUpdate": true,
    "Homepage": {
      "URL": "about:newtab"
     },
 
 
    "Preferences": {
      "dom.private-attribution.submission.enabled": false,
      "browser.tabs.warnOnClose": {
        "Value": true,
        "Status": "default"
      },
       "browser.uidensity": {
	        "Value": 1
        },
        "browser.tabs.inTitlebar": {
	        "Value": 1,
                "Status": "locked"
        },
          "browser.newtabpage.activity-stream.feeds.section.topstories": {
            "Value" : false
        },
        "browser.newtabpage.activity-stream.showSponsored": {
            "Value" : false
        },
         "browser.ml.chat.enabled": {
            "Value" : false        
        },
        "browser.translations.automaticallyPopup": false,
        "browser.urlbar.suggest.trending": false
    },
 
    "DisablePocket": true,
    "DisableTelemetry": true,
 
    "FirefoxHome": {
      "Search": true,
      "TopSites": false,
      "SponsoredTopSites": false,
      "Highlights":  false,
      "Pocket":  false,
      "SponsoredPocket":  false,
      "Snippets": false,
      "Locked": false 
    },
 
    "NoDefaultBookmarks": true,
 
    "OfferToSaveLogins": true,
 
     "OverrideFirstRunPage": "",
     "OverridePostUpdatePage": "",
     "UserMessaging": {
        "WhatsNew": false,
        "ExtensionRecommendations": false,
        "FeatureRecommendations": false,
        "UrlbarInterventions": false,
        "SkipOnboarding": true,
        "MoreFromMozilla":false
      },
 
     "DisableFeedbackCommands": true,
     "DisableFirefoxAccounts": false,
     "DisableBuiltinPDFViewer": false,
 
 
     "SanitizeOnShutdown": false,
 
     "ShowHomeButton": true,
 
     "RequestedLocales": ["fr-FR", "fr"],
     "PromptForDownloadLocation": true,
     "UseSystemPrintDialog": true,
 
     "Extensions": {
      "Install": ["https://addons.mozilla.org/firefox/downloads/latest/dictionnaire-francais1",
                  "https://addons.mozilla.org/firefox/downloads/latest/istilldontcareaboutcookies",
                  "https://addons.mozilla.org/firefox/downloads/latest/sponsorblock",
                  "https://addons.mozilla.org/firefox/downloads/latest/decentraleyes",
                  "https://addons.mozilla.org/firefox/downloads/latest/facebook-container",
                  "https://addons.mozilla.org/firefox/downloads/latest/grammalecte-fr"]
    },
 
    "ExtensionSettings" : {
          "uBlock0@raymondhill.net": {
          "installation_mode": "normal_installed",
           "install_url": "https://addons.mozilla.org/firefox/downloads/latest/ublock-origin/latest.xpi",
           "default_area": "navbar",
           "permissions": [
                 "internal:privateBrowsingAllowed"
                ]
           }
    },
 
    "3rdparty": {
      "Extensions": {
        "uBlock0@raymondhill.net": {
          "adminSettings": {
            "selectedFilterLists": [
                "ublock-privacy",
                "ublock-badware",
                "ublock-filters",
                "ublock-badlists",
                "user-filters",
                "ublock-quick-fixes",
                "ublock-abuse",
                "ublock-unbreak",
                "adguard-generic",
                "adguard-mobile",
                "easylist",
                "adguard-spyware",
                "adguard-spyware-url",
                "block-lan",
                "easyprivacy",
                "urlhaus-1",
                "curben-phishing",
                "curben-pup",
                "adguard-annoyance",
                "adguard-mobile-app-banners",
                "adguard-other-annoyances",
                "adguard-popup-overlays",
                "adguard-social",
                "adguard-widgets",
                "adguard-cookies",              
                "ublock-cookies-adguard",
                "easylist-chat",
                "easylist-newsletters",
                "easylist-notifications",
                "easylist-annoyances",
                "fanboy-thirdparty_social",
                "fanboy-cookiemonster",
                "ublock-cookies-easylist",
                "fanboy-annoyance",
                "fanboy-social",
                "ublock-social",
                "ublock-annoyances",
                "dpollock-0",
                "plowe-0",
                "ara-0",
                "DEU-0",
                "FRA-0"                     
            ]
          }         
        }
      }
    }
 
  }
}

pour débuger si besoin

  "Preferences": {
    "browser.policies.loglevel": {
      "Value": "debug",
      "Status": "locked"
    },