@@ -492,7 +492,7 @@ def write_github_summary(self) -> None:
                                              self.fail_rerun)
         if not self.github_summary or not failed or not exitcode:
             return
-        ncases = sum(len(result.test_cases) for result in failed)
+        ncases = sum(len(result.failed_test_cases) for result in failed)
         with open(self.github_summary, "a", encoding="utf-8") as fp:
             fp.write(f"## {decolor(self.get_state())}: "
                      f"{count(len(failed), 'test file')} and "
@@ -538,8 +538,8 @@ def create_run_tests(self, tests: TestTuple) -> RunTests:
             hunt_refleak=self.hunt_refleak,
             test_dir=self.test_dir,
             use_junit=(self.junit_filename is not None),
-            # Only annotate failures of the last run: not the first run if
-            # failed tests will be re-run (with --python, they are not)
+            # Only annotate the failure that results in job failure.
+            # Ex: When reruning failed tests, only annotate the the final run.
             github_annotations=(bool(self.github_summary) and
                                 not (self.want_rerun and not self.python_cmd)),
             coverage=self.coverage,
@@ -789,8 +789,6 @@ def _init(self):
 
         strip_py_suffix(self.cmdline_args)
 
-        # Pass GitHub Actions annotations to workers in RunTests, not to
-        # regrtest run by tests
         self.github_summary = os.environ.pop("GITHUB_STEP_SUMMARY", None)
 
         self._tmp_dir = get_temp_dir(self._tmp_dir)
 
@@ -184,8 +184,7 @@ def has_meaningful_duration(self):
         return State.has_meaningful_duration(self.state)
 
     @property
-    def test_cases(self) -> list[tuple[str, str]]:
-        """Failed test cases: list of (name, traceback)."""
+    def failed_test_cases(self) -> list[tuple[str, str]]:
         return (self.errors or []) + (self.failures or [])
 
     def format_github_summary(self, expand: bool) -> str:
@@ -194,37 +193,34 @@ def format_github_summary(self, expand: bool) -> str:
         if self.env_changed_reasons:
             blocks.append("\n".join(f"- {reason}"
                                     for reason in self.env_changed_reasons))
-        for name, traceback in self.test_cases:
-            # Expand the tracebacks if they fit on a screen: a traceback of
-            # less than 30 lines
+        for name, traceback in self.failed_test_cases:
+            # Only default open short tracebacks.
             is_open = expand and traceback.count("\n") < 30
             blocks += [f"<details{' open' if is_open else ''}>"
                        f"<summary>{html.escape(name)}</summary>",
                        f"```pytb\n{decolor(traceback).rstrip()}\n```",
                        "</details>"]
+
         # Separate Markdown blocks with an empty line
         return "".join(f"{block}\n\n" for block in blocks)
 
     def print_github_annotation(self, runtests: RunTests) -> None:
-        """Annotate each failed test case, or else the failed test file.
-
-        For example, the test file for a crash, timeout or env changed.
-        """
+        """Print github error annotation line for each failure."""
         if not (runtests.github_annotations
                 and self.is_failed(runtests.fail_env_changed)):
             return
-        # Test file: "test_x" is test_x.py or test_x/__init__.py,
-        # "test.test_x.test_y" is test_x/test_y.py
+        # Convert python import test name to relative file path.
+        # Ex: "test.test_x.test_y" is test_x/test_y.py
         name = self.test_name.removeprefix("test.")
         path = pathlib.Path(findtestdir(runtests.test_dir), *name.split("."))
         filename = path.with_suffix(".py")
         if not filename.exists():
             filename = path / "__init__.py"
-        test_cases = self.test_cases
-        if not test_cases:
+        annotations = self.failed_test_cases
+        if not annotations:
             message = "\n".join([str(self), *(self.env_changed_reasons or ())])
-            test_cases = [(self.test_name, message)]
-        for title, message in test_cases:
+            annotations = [(self.test_name, message)]
+        for title, message in annotations:
             print_github_annotation(title, message, str(filename))
 
     def set_env_changed(self, *reasons):
 
@@ -624,7 +624,6 @@ def _process_result(self, item: QueueOutput) -> TestResult:
             stdout = mp_result.worker_stdout
             if stdout:
                 print(stdout, flush=True)
-        # Annotate after the output: env changed warnings, crash traceback
         result.print_github_annotation(self.runtests)
 
         return result
 
@@ -149,25 +149,20 @@ def print_warning(msg: str) -> None:
 
 
 def print_github_annotation(title: str, message: str, filename: str) -> None:
-    """Print a GitHub Actions error annotation.
-
-    message is a traceback or a failure description. Only keep the exception
-    which ends the traceback: the job log has the full traceback. Locate the
-    annotation at the last traceback frame in a test file, or else at the
-    first frame (the test), or else in filename (the test file).
-    """
+    """Print a GitHub Actions error annotation for the failure."""
     if not filename:
-        raise ValueError(f"missing test file of annotation {title!r}")
+        raise ValueError(f"missing filename to annotate {title!r}")
     message = decolor(message)
+
+    # Try to get a line number from backtrace.
     line = None
-    # Traceback frames ('  File "filename", line 123') and failed doctest
-    # examples (same, but not indented)
     if frames := re.findall(r'^ *File "(.*)", line (\d+)', message,
                             re.MULTILINE):
         test_frames = [frame for frame in frames
                        if pathlib.Path(frame[0]).name.startswith('test_')]
         filename, line = test_frames[-1] if test_frames else frames[0]
-    # In the job, the stdlib can be outside of the repository checkout
+
+    # Normalize stdlib path to be relative inside the repository checkout.
     path = pathlib.Path(filename)
     stdlib_dir = pathlib.Path(os.__file__).parent
     if path.is_relative_to(stdlib_dir):