Firefox from version 74 and above requires the mdm profile to get deployed to enable the plugin
Release : 15.x
Component : edpa
Firefox v74 and above.
Mozilla made changes to their browsers and how you can enable third party plugins.
you can create a profile using the following xml.
<?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>EnterprisePoliciesEnabled</key>
<true/>
<key>ExtensionSettings</key>
<dict>
<key>*</key>
<dict>
<key>blocked_install_message</key>
<string>Custom error message.</string>
<key>install_sources</key>
<array>
<string>*</string>
</array>
<key>installation_mode</key>
<string>allowed</string>
<key>allowed_types</key>
<array>
<string>extension</string>
</array>
</dict>
<key>[email protected]</key>
<dict>
<key>installation_mode</key>
<string>force_installed</string>
<key>install_url</key>
<string>file:////Library/Manufacturer/Endpoint Agent/dlp-firefox-addon.xpi</string>
</dict>
</dict>
</dict>
</plist>