diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 56f231d9578..d96b79148ee 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -96,39 +96,6 @@ jobs:
           MAKE: make -j2 --output-sync=recurse
           SAGE_NUM_THREADS: 2
 
-      - name: Build modularized distributions
-        if: (success() || failure()) && steps.worktree.outcome == 'success'
-        run: make V=0 tox && make SAGE_CHECK=no pypi-wheels
-        working-directory: ./worktree-image
-        env:
-          MAKE: make -j2 --output-sync=recurse
-          SAGE_NUM_THREADS: 2
-
-      - name: Static code check with pyright
-        if: (success() || failure()) && steps.worktree.outcome == 'success'
-        uses: jakebailey/pyright-action@v1
-        with:
-          version: 1.1.332
-          # Many warnings issued by pyright are not yet helpful because there is not yet enough type information.
-          no-comments: true
-          working-directory: ./worktree-image
-        env:
-          # To avoid out of memory errors
-          NODE_OPTIONS: --max-old-space-size=8192
-      
-      - name: Static code check with pyright (annotated)
-        if: (success() || failure()) && steps.worktree.outcome == 'success'
-        uses: jakebailey/pyright-action@v1
-        with:
-          version: 1.1.332
-          # Issue errors
-          no-comments: false
-          level: error
-          working-directory: ./worktree-image
-        env:
-          # To avoid out of memory errors
-          NODE_OPTIONS: --max-old-space-size=8192
-
       - name: Clean (fallback to non-incremental)
         id: clean
         if: (success() || failure()) && steps.worktree.outcome == 'success' && steps.incremental.outcome != 'success'
@@ -187,9 +154,9 @@ jobs:
       - name: Pytest
         if: contains(github.ref, 'pytest')
         run: |
-          ../sage -python -m pip install coverage pytest-xdist
-          ../sage -python -m coverage run -m pytest -c tox.ini --doctest || true
-        working-directory: ./worktree-image/src
+          ./sage -python -m pip install coverage pytest-xdist
+          ./sage -python -m coverage run --rcfile=src/tox.ini -m pytest -c src/tox.ini --doctest-modules || true
+        working-directory: ./worktree-image
         env:
           # Increase the length of the lines in the "short summary"
           COLUMNS: 120
@@ -197,21 +164,15 @@ jobs:
       - name: Test all files (sage -t --all --long)
         if: (success() || failure()) && steps.build.outcome == 'success'
         run: |
-          ../sage -python -m pip install coverage
-          ../sage -python -m coverage run ./bin/sage-runtests --all --long -p2 --random-seed=286735480429121101562228604801325644303
-        working-directory: ./worktree-image/src
+          ./sage -python -m pip install coverage
+          ./sage -python -m coverage run --rcfile=src/tox.ini src/bin/sage-runtests --all --long -p2 --format github --random-seed=286735480429121101562228604801325644303
+        working-directory: ./worktree-image
 
       - name: Prepare coverage results
         if: (success() || failure()) && steps.build.outcome == 'success'
         run: |
-          ./venv/bin/python3 -m coverage combine src/.coverage/
-          ./venv/bin/python3 -m coverage xml
+          ./sage -python -m coverage combine --rcfile=src/tox.ini
+          ./sage -python -m coverage xml --rcfile=src/tox.ini
           mkdir -p coverage-report
           mv coverage.xml coverage-report/
         working-directory: ./worktree-image
-
-      - name: Upload coverage to codecov
-        if: (success() || failure()) && steps.build.outcome == 'success'
-        uses: codecov/codecov-action@v3
-        with:
-          directory: ./worktree-image/coverage-report
diff --git a/.github/workflows/ci-conda-known-test-failures.json b/.github/workflows/ci-conda-known-test-failures.json
index 2d828ac98fb..47d0adcd8e9 100644
--- a/.github/workflows/ci-conda-known-test-failures.json
+++ b/.github/workflows/ci-conda-known-test-failures.json
@@ -1,12 +1,18 @@
 {
+    "doc.en.constructions.calculus": {
+        "failed": "unreported random failures in plotting"
+    },
     "sage_setup.clean": {
-        "failed": true
+        "failed": "_find_stale_files finds some stale files under sage/tests when executed under conda"
+    },
+    "sage.algebras.fusion_rings.fusion_ring": {
+        "failed": "unreported random timeouts"
     },
     "sage.combinat.cluster_algebra_quiver.quiver": {
-        "failed": true
+        "failed": "failure seen in https://github.com/sagemath/sage/actions/runs/6836592771/job/18591690058#step:11:10059"
     },
     "sage.geometry.cone": {
-        "failed": true
+        "failed": "unreported random timeouts seen in https://github.com/sagemath/sage/actions/runs/6827937663/job/18571052628#step:11:12362"
     },
     "sage.groups.matrix_gps.finitely_generated_gap": {
         "failed": true
@@ -15,28 +21,34 @@
         "failed": true
     },
     "sage.libs.gap.element": {
-        "failed": true
+        "failed": "failure seen in https://github.com/sagemath/sage/actions/runs/6840579851/job/18600012965#step:11:13016"
     },
     "sage.libs.singular.singular": {
         "failed": true
     },
     "sage.matrix.matrix2": {
-        "failed": true
+        "failed": "failure seen in https://github.com/sagemath/sage/actions/runs/6835143781/job/18588599649#step:11:16939"
     },
     "sage.matrix.matrix_integer_sparse": {
-        "failed": true
+        "failed": "failure seen in https://github.com/sagemath/sage/actions/runs/6827937663/job/18571052628#step:11:12362"
     },
     "sage.misc.lazy_import": {
         "failed": true
     },
     "sage.misc.weak_dict": {
-        "failed": true
+        "failed": "failure seen in https://github.com/sagemath/sage/actions/runs/6870325919/job/18684964234#step:11:10059"
     },
     "sage.modular.modform.l_series_gross_zagier": {
-        "failed": true
+        "failed": "unreported failure seen in https://github.com/sagemath/sage/actions/runs/6859244281/job/18651257775#step:11:10102"
+    },
+    "sage.parallel.map_reduce": {
+        "failed": "random failure https://github.com/sagemath/sage/issues/36939"
+    },
+    "sage.plot.plot": {
+        "failed": "unreported random failure (macOS)"
     },
     "sage.rings.function_field.drinfeld_modules.morphism": {
-        "failed": true
+        "failed": "unreported random failure seen in https://github.com/sagemath/sage/actions/runs/6840502530/job/18599835766#step:11:10107"
     },
     "sage.rings.polynomial.multi_polynomial_ideal": {
         "failed": true
@@ -44,9 +56,21 @@
     "sage.rings.polynomial.multi_polynomial_libsingular": {
         "failed": true
     },
+    "sage.rings.polynomial.polynomial_element": {
+        "failed": "unreported random failure in symbolic 'roots' (macOS)"
+    },
     "sage.rings.polynomial.skew_polynomial_finite_field": {
         "failed": true
     },
+    "sage.schemes.elliptic_curves.ell_field": {
+        "failed": "random failure https://github.com/sagemath/sage/issues/36832"
+    },
+    "sage.sets.recursively_enumerated_set": {
+        "failed": "random failures related to AlarmInterrupt (macOS)"
+    },
+    "sage.structure.coerce_actions": {
+        "failed": "random failure https://github.com/sagemath/sage/issues/35973"
+    },
     "sage.tests.gap_packages": {
         "failed": true
     }
diff --git a/.github/workflows/ci-conda.yml b/.github/workflows/ci-conda.yml
deleted file mode 100644
index 7fac038718c..00000000000
--- a/.github/workflows/ci-conda.yml
+++ /dev/null
@@ -1,101 +0,0 @@
-name: Build & Test using Conda
-
-on:
-  push:
-    tags:
-      - '*'
-    branches:
-      - 'public/build/**-runci'
-  pull_request:
-  workflow_dispatch:
-    # Allow to run manually
-
-concurrency:
-  # Cancel previous runs of this workflow for the same branch
-  group: ${{ github.workflow }}-${{ github.ref }}
-  cancel-in-progress: true
-
-jobs:
-  test:
-    name: Conda
-    runs-on: ${{ matrix.os }}-latest
-
-    strategy:
-      matrix:
-        os: [ubuntu, macos]
-        python: ['3.9', '3.10', '3.11']
-        # Optional environment is disabled for now as its not yet working
-        # environment: [environment, environment-optional]
-        conda-env: [environment]
-
-    steps:
-      - uses: actions/checkout@v4
-
-      - name: Merge CI fixes from sagemath/sage
-        run: |
-          .ci/merge-fixes.sh
-        env:
-          GH_TOKEN: ${{ github.token }}
-          SAGE_CI_FIXES_FROM_REPOSITORIES: ${{ vars.SAGE_CI_FIXES_FROM_REPOSITORIES }}
-
-      - name: Cache conda packages
-        uses: actions/cache@v3
-        with:
-          path: ~/conda_pkgs_dir
-          key:
-            ${{ runner.os }}-conda-${{ hashFiles('src/environment-3.11.yml') }}
-
-      - name: Setup Conda environment
-        uses: conda-incubator/setup-miniconda@v2
-        with:
-          python-version: ${{ matrix.python }}
-          miniforge-version: latest
-          use-mamba: true
-          channels: conda-forge
-          channel-priority: true
-          activate-environment: sage
-          environment-file: src/${{ matrix.conda-env }}-${{ matrix.python }}-${{ startsWith(matrix.os, 'macos') && 'macos' || 'linux' }}.yml
-
-      - name: Print Conda environment
-        shell: bash -l {0}
-        run: |
-          conda info
-          conda list
-
-      - name: Configure
-        shell: bash -l {0}
-        continue-on-error: true
-        run: |
-          ./bootstrap
-          echo "::add-matcher::.github/workflows/configure-systempackage-problem-matcher.json"
-          ./configure --enable-build-as-root --with-python=$CONDA_PREFIX/bin/python --prefix=$CONDA_PREFIX --enable-system-site-packages $(for pkg in $(./sage -package list :standard: --has-file spkg-configure.m4 --has-file distros/conda.txt --exclude rpy2); do echo --with-system-$pkg=force; done)
-          echo "::remove-matcher owner=configure-system-package-warning::"
-          echo "::remove-matcher owner=configure-system-package-error::"
-
-      - name: Build
-        shell: bash -l {0}
-        run: |
-          # Use --no-deps and pip check below to verify that all necessary dependencies are installed via conda.
-          pip install --no-build-isolation --no-deps -v -v -e ./pkgs/sage-conf ./pkgs/sage-setup
-          pip install --no-build-isolation --no-deps --config-settings editable_mode=compat -v -v -e ./src
-        env:
-          SAGE_NUM_THREADS: 2
-        
-      - name: Verify dependencies
-        if: success() || failure()
-        shell: bash -l {0}
-        run: pip check
-
-      - name: Test
-        if: success() || failure()
-        shell: bash -l {0}
-        run: ./sage -t --all --baseline-stats-path=.github/workflows/ci-conda-known-test-failures.json -p0
-
-      - name: Print logs
-        if: always()
-        run: |
-          for file in $(find . -type f -name "*.log"); do
-              echo "::group::$file"
-              cat "$file"
-              echo "::endgroup::"
-          done
diff --git a/src/bin/sage-runtests b/src/bin/sage-runtests
index 4a8b05cfab6..81efd01a4d8 100755
--- a/src/bin/sage-runtests
+++ b/src/bin/sage-runtests
@@ -34,6 +34,8 @@ if __name__ == "__main__":
     what.add_argument("--installed", action="store_true", default=False, help="test all installed modules of the Sage library")
     parser.add_argument("--logfile", type=argparse.FileType('a'), metavar="FILE", help="log all output to FILE")
 
+    parser.add_argument("--format", choices=["sage", "github"], default="sage",
+                        help="set format of error messages and warnings")
     parser.add_argument("-l", "--long", action="store_true", default=False, help="include lines with the phrase 'long time'")
     parser.add_argument("-s", "--short", dest="target_walltime", nargs='?',
                         type=int, default=-1, const=300, metavar="SECONDS",
diff --git a/src/sage/combinat/words/word.py b/src/sage/combinat/words/word.py
index 222501a5dfd..f74656317f2 100644
--- a/src/sage/combinat/words/word.py
+++ b/src/sage/combinat/words/word.py
@@ -147,7 +147,7 @@ def Word(data=None, alphabet=None, length=None, datatype=None, caching=True, RSK
 
     Word over a string with a parent::
 
-        sage: w = Word("abbabaab", alphabet="abc"); w
+        sage: w = Word("abbabaab", daslkdlsakdlksaldkasldklsakdlsak, alphabet="abc"); w
         word: abbabaab
         sage: w.parent()
         Finite words over {'a', 'b', 'c'}
@@ -252,7 +252,7 @@ class FiniteWord_char(WordDatatype_char, FiniteWord_class):
         True
 
         sage: w.is_square_free()
-        False
+        Falsish
         sage: w[:-1].is_square_free()
         True
 
diff --git a/src/sage/doctest/control.py b/src/sage/doctest/control.py
index 1a128983187..396f5e28263 100644
--- a/src/sage/doctest/control.py
+++ b/src/sage/doctest/control.py
@@ -139,6 +139,7 @@ def __init__(self, **kwds):
         self.show_skipped = False
         self.target_walltime = -1
         self.baseline_stats_path = None
+        self.format = "sage"
 
         # sage-runtests contains more optional tags. Technically, adding
         # auto_optional_tags here is redundant, since that is added
diff --git a/src/sage/doctest/forker.py b/src/sage/doctest/forker.py
index fce553543bb..9590c8a2faa 100644
--- a/src/sage/doctest/forker.py
+++ b/src/sage/doctest/forker.py
@@ -1235,16 +1235,57 @@ def _failure_header(self, test, example, message='Failed example:'):
         """
         out = [self.DIVIDER]
         with OriginalSource(example):
-            if test.filename:
-                if test.lineno is not None and example.lineno is not None:
-                    lineno = test.lineno + example.lineno + 1
+            if self.options.format == 'sage':
+                if test.filename:
+                    if test.lineno is not None and example.lineno is not None:
+                        lineno = test.lineno + example.lineno + 1
+                    else:
+                        lineno = '?'
+                    out.append('File "%s", line %s, in %s' %
+                               (test.filename, lineno, test.name))
+                else:
+                    out.append('Line %s, in %s' % (example.lineno + 1, test.name))
+                out.append(message)
+            elif self.options.format == 'github':
+                # https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#using-workflow-commands-to-access-toolkit-functions
+                if message.startswith('Warning: '):
+                    command = f'::warning title={message}'
+                    message = message[len('Warning: '):]
+                elif self.baseline.get('failed', False):
+                    command = f'::notice title={message}'
+                    message += ' [failed in baseline]'
                 else:
-                    lineno = '?'
-                out.append('File "%s", line %s, in %s' %
-                           (test.filename, lineno, test.name))
+                    command = f'::error title={message}'
+                if extra := getattr(example, 'extra', None):
+                    message += f': {extra}'
+                if test.filename:
+                    command += f',file={test.filename}'
+                    if test.lineno is not None and example.lineno is not None:
+                        lineno = test.lineno + example.lineno + 1
+                        command += f',line={lineno}'
+                    lineno = None
+                else:
+                    command += f',line={example.lineno + 1}'
+                #
+                # Urlencoding trick for multi-line annotations
+                # https://github.com/actions/starter-workflows/issues/68#issuecomment-581479448
+                #
+                # This only affects the display in the workflow Summary, after clicking "Show more";
+                # the message needs to be long enough so that "Show more" becomes available.
+                # https://github.com/actions/toolkit/issues/193#issuecomment-1867084340
+                #
+                # Unfortunately, this trick does not make the annotations in the diff view multi-line.
+                #
+                if '\n' in message:
+                    message = message.replace('\n', '%0A')
+                    # The actual threshold for "Show more" to appear depends on the window size.
+                    show_more_threshold = 500
+                    if (pad := show_more_threshold - len(message)) > 0:
+                        message += ' ' * pad
+                command += f'::{message}'
+                out.append(command)
             else:
-                out.append('Line %s, in %s' % (example.lineno + 1, test.name))
-            out.append(message)
+                raise ValueError(f'unknown format option: {self.options.format}')
             source = example.source
             out.append(doctest._indent(source))
             return '\n'.join(out)
@@ -1417,6 +1458,7 @@ def report_failure(self, out, test, example, got, globs):
         """
         if not self.options.initial or self.no_failure_yet:
             self.no_failure_yet = False
+            example.extra = f'Got: {got}'
             returnval = doctest.DocTestRunner.report_failure(self, out, test, example, got)
             if self.options.debug:
                 self._fakeout.stop_spoofing()
@@ -1567,6 +1609,8 @@ def report_unexpected_exception(self, out, test, example, exc_info):
         """
         if not self.options.initial or self.no_failure_yet:
             self.no_failure_yet = False
+
+            example.extra = "Exception raised:\n" + "".join(traceback.format_exception(*exc_info))
             returnval = doctest.DocTestRunner.report_unexpected_exception(self, out, test, example, exc_info)
             if self.options.debug:
                 self._fakeout.stop_spoofing()
diff --git a/src/sage/doctest/reporting.py b/src/sage/doctest/reporting.py
index 993ebeaa7a1..9fab0e966bd 100644
--- a/src/sage/doctest/reporting.py
+++ b/src/sage/doctest/reporting.py
@@ -213,10 +213,13 @@ def report_head(self, source, fail_msg=None):
         baseline = self.controller.source_baseline(source)
         if fail_msg:
             cmd += "  # " + fail_msg
-        if baseline.get('failed', False):
+        if failed := baseline.get('failed', False):
             if not fail_msg:
                 cmd += "  #"
-            cmd += " [failed in baseline]"
+            if failed is True:
+                cmd += " [failed in baseline]"
+            else:
+                cmd += f" [failed in baseline: {failed}]"
         return cmd
 
     def report(self, source, timeout, return_code, results, output, pid=None):
diff --git a/src/sage_setup/clean.py b/src/sage_setup/clean.py
index e9c81c9ed1a..bac2ed26417 100644
--- a/src/sage_setup/clean.py
+++ b/src/sage_setup/clean.py
@@ -101,7 +101,7 @@ def _find_stale_files(site_packages, python_packages, python_modules, ext_module
         sage: stale_iter = _find_stale_files(SAGE_LIB, python_packages, python_modules, [], extra_files)
         sage: from importlib.machinery import EXTENSION_SUFFIXES
         sage: skip_extensions = tuple(EXTENSION_SUFFIXES)
-        sage: for f in stale_iter:
+        sage: for f in stale_iter:dxfcgvhbjkl;,mkjnbhgvcfgvhbjnkml,
         ....:     if f.endswith(skip_extensions): continue
         ....:     if '/ext_data/' in f: continue
         ....:     print('Found stale file: ' + f)
diff --git a/src/tox.ini b/src/tox.ini
index 00f7a153f35..f2f1fc158fd 100644
--- a/src/tox.ini
+++ b/src/tox.ini
@@ -299,3 +299,7 @@ source = sage
 concurrency = multiprocessing
 data_file = .coverage/.coverage
 disable_warnings = no-data-collected
+
+[coverage:report]
+ignore_errors = True
+skip_empty = True