Chrome Enterprise Linux policy - allows all hosted extensions and uBlock-Origin

managed_policy.json

# Allows install of any locally hosted extensions, restricts webstore extensions without explicit allow.
{
  "HomepageLocation": "https://www.google.com",
  "HomepageIsNewTabPage": false,
  "ExtensionSettings": {
    "*": {
      "installation_mode": "blocked",
      "blocked_install_message": "Extension installation is restricted to reviewed and approved only.",
      "blocked_permissions": [],
      "install_sources": [
        "*://localhost:8000/*",
        "http://127.0.0.1:8000/*",
        "file:///*"
      ]
    },
    "cjpalhdlnbpafiamejdnhcphjbkeiagm": {
      "installation_mode": "allowed",
      "override_update_url": true,
      "toolbar_pin": "force_pinned"
    }
  }
}