diff --git a/tools/manifest/item.py b/tools/manifest/item.py
index 6601f9c719e040..ee07f0d1d79717 100644
--- a/tools/manifest/item.py
+++ b/tools/manifest/item.py
@@ -212,7 +212,7 @@ def to_json(self):
         if self.quic is not None:
             rv[-1]["quic"] = self.quic
         if self.script_metadata:
-            rv[-1]["script_metadata"] = [(k.decode('utf8'), v.decode('utf8')) for (k,v) in self.script_metadata]
+            rv[-1]["script_metadata"] = [(k, v) for (k,v) in self.script_metadata]
         return rv
 
 
diff --git a/tools/manifest/sourcefile.py b/tools/manifest/sourcefile.py
index f36ce1ab3304d7..659a1bb1366b8c 100644
--- a/tools/manifest/sourcefile.py
+++ b/tools/manifest/sourcefile.py
@@ -70,16 +70,16 @@ def read_script_metadata(f, regexp):
         if not m:
             break
 
-        yield (m.groups()[0], m.groups()[1])
+        yield (m.groups()[0].decode("utf8"), m.groups()[1].decode("utf8"))
 
 
 _any_variants = {
-    b"window": {"suffix": ".any.html"},
-    b"serviceworker": {"force_https": True},
-    b"sharedworker": {},
-    b"dedicatedworker": {"suffix": ".any.worker.html"},
-    b"worker": {"longhand": {b"dedicatedworker", b"sharedworker", b"serviceworker"}},
-    b"jsshell": {"suffix": ".any.js"},
+    "window": {"suffix": ".any.html"},
+    "serviceworker": {"force_https": True},
+    "sharedworker": {},
+    "dedicatedworker": {"suffix": ".any.worker.html"},
+    "worker": {"longhand": {"dedicatedworker", "sharedworker", "serviceworker"}},
+    "jsshell": {"suffix": ".any.js"},
 }  # type: Dict[bytes, Dict[str, Any]]
 
 
@@ -88,7 +88,7 @@ def get_any_variants(item):
     """
     Returns a set of variants (bytestrings) defined by the given keyword.
     """
-    assert isinstance(item, binary_type), item
+    assert isinstance(item, text_type), item
 
     variant = _any_variants.get(item, None)
     if variant is None:
@@ -102,42 +102,46 @@ def get_default_any_variants():
     """
     Returns a set of variants (bytestrings) that will be used by default.
     """
-    return set({b"window", b"dedicatedworker"})
+    return set({"window", "dedicatedworker"})
 
 
 def parse_variants(value):
-    # type: (bytes) -> Set[bytes]
+    # type: (Text) -> Set[Text]
     """
     Returns a set of variants (bytestrings) defined by a comma-separated value.
     """
-    assert isinstance(value, binary_type), value
+    assert isinstance(value, text_type), value
 
-    if value == b"":
+    if value == "":
         return get_default_any_variants()
 
     globals = set()
-    for item in value.split(b","):
+    for item in value.split(","):
         item = item.strip()
         globals |= get_any_variants(item)
     return globals
 
 
 def global_suffixes(value):
-    # type: (bytes) -> Set[Tuple[bytes, bool]]
+    # type: (Text) -> Set[Tuple[Text, bool]]
     """
     Yields tuples of the relevant filename suffix (a string) and whether the
     variant is intended to run in a JS shell, for the variants defined by the
     given comma-separated value.
     """
-    assert isinstance(value, binary_type), value
+    try:
+        assert isinstance(value, text_type), value
+    except Exception:
+        import pdb
+        pdb.post_mortem()
 
     rv = set()
 
     global_types = parse_variants(value)
     for global_type in global_types:
         variant = _any_variants[global_type]
-        suffix = variant.get("suffix", ".any.%s.html" % global_type.decode("utf-8"))
-        rv.add((suffix, global_type == b"jsshell"))
+        suffix = variant.get("suffix", ".any.%s.html" % global_type)
+        rv.add((suffix, global_type == "jsshell"))
 
     return rv
 
@@ -462,7 +466,7 @@ def timeout_nodes(self):
 
     @cached_property
     def script_metadata(self):
-        # type: () -> Optional[List[Tuple[bytes, bytes]]]
+        # type: () -> Optional[List[Tuple[Text, Text]]]
         if self.name_is_worker or self.name_is_multi_global or self.name_is_window:
             regexp = js_meta_re
         elif self.name_is_webdriver:
@@ -479,7 +483,7 @@ def timeout(self):
         """The timeout of a test or reference file. "long" if the file has an extended timeout
         or None otherwise"""
         if self.script_metadata:
-            if any(m == (b"timeout", b"long") for m in self.script_metadata):
+            if any(m == ("timeout", "long") for m in self.script_metadata):
                 return "long"
 
         if self.root is None:
@@ -641,8 +645,8 @@ def test_variants(self):
             script_metadata = self.script_metadata
             assert script_metadata is not None
             for (key, value) in script_metadata:
-                if key == b"variant":
-                    rv.append(value.decode("utf-8"))
+                if key == "variant":
+                    rv.append(value)
         else:
             for element in self.variant_nodes:
                 if "content" in element.attrib:
@@ -864,11 +868,11 @@ def manifest_items(self):
                 )]
 
         elif self.name_is_multi_global:
-            globals = b""
+            globals = u""
             script_metadata = self.script_metadata
             assert script_metadata is not None
             for (key, value) in script_metadata:
-                if key == b"global":
+                if key == "global":
                     globals = value
                     break
 
diff --git a/tools/manifest/tests/test_sourcefile.py b/tools/manifest/tests/test_sourcefile.py
index a8fbc27071408d..ae9a530a093b19 100644
--- a/tools/manifest/tests/test_sourcefile.py
+++ b/tools/manifest/tests/test_sourcefile.py
@@ -180,7 +180,7 @@ def test_worker_long_timeout():
 test()"""
 
     metadata = list(read_script_metadata(BytesIO(contents), js_meta_re))
-    assert metadata == [(b"timeout", b"long")]
+    assert metadata == [("timeout", "long")]
 
     s = create("html/test.worker.js", contents=contents)
     assert s.name_is_worker
@@ -197,7 +197,7 @@ def test_window_long_timeout():
 test()"""
 
     metadata = list(read_script_metadata(BytesIO(contents), js_meta_re))
-    assert metadata == [(b"timeout", b"long")]
+    assert metadata == [("timeout", "long")]
 
     s = create("html/test.window.js", contents=contents)
     assert s.name_is_window
@@ -278,7 +278,7 @@ def test_python_long_timeout():
 
     metadata = list(read_script_metadata(BytesIO(contents),
                                          python_meta_re))
-    assert metadata == [(b"timeout", b"long")]
+    assert metadata == [("timeout", "long")]
 
     s = create("webdriver/test.py", contents=contents)
     assert s.name_is_webdriver
@@ -322,7 +322,7 @@ def test_multi_global_long_timeout():
 test()"""
 
     metadata = list(read_script_metadata(BytesIO(contents), js_meta_re))
-    assert metadata == [(b"timeout", b"long")]
+    assert metadata == [("timeout", "long")]
 
     s = create("html/test.any.js", contents=contents)
     assert s.name_is_multi_global
diff --git a/tools/serve/serve.py b/tools/serve/serve.py
index 45bfd4766ebcd2..4bacf65640c22c 100644
--- a/tools/serve/serve.py
+++ b/tools/serve/serve.py
@@ -178,9 +178,9 @@ class HtmlWrapperHandler(WrapperHandler):
 
     def check_exposure(self, request):
         if self.global_type:
-            globals = b""
+            globals = ""
             for (key, value) in self._get_metadata(request):
-                if key == b"global":
+                if key == "global":
                     globals = value
                     break
 
@@ -189,17 +189,17 @@ def check_exposure(self, request):
                                     self.global_type)
 
     def _meta_replacement(self, key, value):
-        if key == b"timeout":
-            if value == b"long":
+        if key == "timeout":
+            if value == "long":
                 return '<meta name="timeout" content="long">'
-        if key == b"title":
-            value = value.decode('utf-8').replace("&", "&amp;").replace("<", "&lt;")
+        if key == "title":
+            value = value.replace("&", "&amp;").replace("<", "&lt;")
             return '<title>%s</title>' % value
         return None
 
     def _script_replacement(self, key, value):
-        if key == b"script":
-            attribute = value.decode('utf-8').replace("&", "&amp;").replace('"', "&quot;")
+        if key == "script":
+            attribute = value.replace("&", "&amp;").replace('"', "&quot;")
             return '<script src="%s"></script>' % attribute
         return None
 
@@ -307,11 +307,11 @@ def _meta_replacement(self, key, value):
         return None
 
     def _script_replacement(self, key, value):
-        if key == b"script":
-            attribute = value.decode('utf-8').replace("\\", "\\\\").replace('"', '\\"')
+        if key == "script":
+            attribute = value.replace("\\", "\\\\").replace('"', '\\"')
             return 'importScripts("%s")' % attribute
-        if key == b"title":
-            value = value.decode('utf-8').replace("\\", "\\\\").replace('"', '\\"')
+        if key == "title":
+            value = value.replace("\\", "\\\\").replace('"', '\\"')
             return 'self.META_TITLE = "%s";' % value
         return None
 
diff --git a/tools/wptrunner/wptrunner/wpttest.py b/tools/wptrunner/wptrunner/wpttest.py
index 4b43b73610a591..6b0fab6eebaf50 100644
--- a/tools/wptrunner/wptrunner/wpttest.py
+++ b/tools/wptrunner/wptrunner/wpttest.py
@@ -411,7 +411,7 @@ def from_manifest(cls, manifest_file, manifest_item, inherit_metadata, test_meta
         quic = manifest_item.quic if hasattr(manifest_item, "quic") else False
         script_metadata = manifest_item.script_metadata or []
         scripts = [v for (k, v) in script_metadata
-                   if k in (b"script", "script")]
+                   if k == "script"]
         return cls(manifest_file.tests_root,
                    manifest_item.url,
                    inherit_metadata,