diff --git a/testing/web-platform/tests/webdriver/tests/support/inline.py b/testing/web-platform/tests/webdriver/tests/support/inline.py
index a0a8d3881ef5..26f0491d1a87 100644
--- a/testing/web-platform/tests/webdriver/tests/support/inline.py
+++ b/testing/web-platform/tests/webdriver/tests/support/inline.py
@@ -1,6 +1,6 @@
 """Helpers for inlining extracts of documents in tests."""
 
-from typing import Literal, Optional
+from typing import Optional
 from urllib.parse import urlencode
 
 
@@ -27,7 +27,7 @@ MIME_TYPES = {
 
 
 def build_inline(build_url, src,
-                 doctype: Literal["html", "xhtml", "xml"] = "html",
+                 doctype: str = "html",
                  mime: Optional[str] = None, charset: Optional[str] = None,
                  parameters = None, **kwargs):
     if mime is None: