I find for best results to use iMazing profile editor. https://imazing.com/ It has a customizable form with all the keys to Firefox and plenty of other 3rd party apps
you can use the below code to install Extensions for firefox, For More information please refer the below link
https://mozilla.github.io/policy-templates/#extensions
<dict>
<key>Extensions</key>
<dict>
<key>Install</key>
<array>
<string>https://addons.mozilla.org/firefox/downloads/somefile.xpi</string>
<string>//path/to/xpi</string>
</array>
<key>Uninstall</key>
<array>
<string>bad_addon_id@mozilla.org</string>
</array>
<key>Locked</key>
<array>
<string>addon_id@mozilla.org</string>
</array>
</dict>
</dict>
you can use the below code to install Extensions for firefox, For More information please refer the below link
https://mozilla.github.io/policy-templates/#extensions
<dict>
<key>Extensions</key>
<dict>
<key>Install</key>
<array>
<string>https://addons.mozilla.org/firefox/downloads/somefile.xpi</string>
<string>//path/to/xpi</string>
</array>
<key>Uninstall</key>
<array>
<string>bad_addon_id@mozilla.org</string>
</array>
<key>Locked</key>
<array>
<string>addon_id@mozilla.org</string>
</array>
</dict>
</dict>
I don't have a problem installing it, but it's for configuring the extension, I want to make a PLIST like for Chrome. Otherwise I have to put my JSON file in the package. The configuration I want to do is specific to the extension and not to all extensions. The link doesn't give me any information about this (preferred domain, etc.).
I recently had the same question, and found an answer: Unlike in chrome, you don't use a separate preference domain for configuring the settings for an individual extension. Instead, you use the "3rdparty" key in Firefox policy and you can set individual extension settings underneath that.
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I don't use this extension, but this company provides deployment instructions (with configuring settings in their extension) for their extension for both Chrome + Firefox, so you can see what I'm talking about/compare differences: https://help.cerby.com/en/articles/8265232-install-the-cerby-browser-extension-via-an-mdm-service-and-a-configuration-file
Here's their Firefox config - the part under ExtensionSettings is what deploys the extension, but the part under 3rdparty is what configures a setting within that extension:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>ExtensionSettings</key>
<dict>
<key>{f961ea35-985c-412d-9b06-aafd75752587}</key>
<dict>
<key>installation_mode</key>
<string>force_installed</string>
<key>install_url</key>
<string>https://addons.mozilla.org/firefox/downloads/latest/cerby-s-browser-extension/latest.xpi</string>
</dict>
</dict>
<key>3rdparty</key>
<dict>
<key>Extensions</key>
<dict>
<key>{f961ea35-985c-412d-9b06-aafd75752587}</key>
<dict>
<key>DEFAULT_WORKSPACE</key>
<string>{your-workspace-name}</string>
</dict>
</dict>
</dict>
<key>EnterprisePoliciesEnabled</key>
<true/>
</dict>
</plist>