We could use:
https://github.com/mozilla/pdf.js/blob/c3d08580627471432a6ad0b2fdb948df64126afa/src/display/api.js#L929

and look at bit 4.

The following pdf:
https://orimi.com/pdf-test.pdf
is not editable in neither Acrobat nor Edge nor Foxit and nor Okular.
value: "canvas",
    kind: OptionKind.VIEWER + OptionKind.PREFERENCE,
  };
  defaultOptions.sandboxBundleSrc = {
    
    value:
      typeof PDFJSDev === "undefined" || !PDFJSDev.test("PRODUCTION")
        ? "../build/dev-sandbox/pdf.sandbox.js"
        : "../build/pdf.sandbox.js",
    kind: OptionKind.VIEWER,
  };
} else if (PDFJSDev.test("CHROME")) {
  defaultOptions.defaultUrl = {
    
    value: "",
    kind: OptionKind.VIEWER,
  };
  defaultOptions.disableTelemetry = {
    
    value: false,
    kind: OptionKind.VIEWER + OptionKind.PREFERENCE,
  };
  defaultOptions.sandboxBundleSrc = {
    
    value: "../build/pdf.sandbox.js",
    kind: OptionKind.VIEWER,
  };
}
const userOptions = Object.create(null);
class AppOptions {