diff --git a/.github/workflows/reusable_build_wheels.yaml b/.github/workflows/_build_wheels.yaml
similarity index 100%
rename from .github/workflows/reusable_build_wheels.yaml
rename to .github/workflows/_build_wheels.yaml
diff --git a/.github/workflows/reusable_find_changes.yaml b/.github/workflows/_find_changes.yaml
similarity index 58%
rename from .github/workflows/reusable_find_changes.yaml
rename to .github/workflows/_find_changes.yaml
index 87803e599..3c70ab3f1 100644
--- a/.github/workflows/reusable_find_changes.yaml
+++ b/.github/workflows/_find_changes.yaml
@@ -21,8 +21,8 @@
 # protection rules work is: "If a workflow is skipped due to path filtering
 # [...] the checks associated with that workflow will remain in a Pending
 # state. A PR that requires those checks to be successful will be blocked from
-# merging." This makes path filters unusable with merge queues. We forgo the
-# use of path filters, and instead check file changes using our own workflow.
+# merging." This makes path filters unusable with merge queues. So, we forgo the
+# use of path filters and instead check file changes using our own workflow.
 # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 # The tilde is only to make our reusable workflows be listed last in the UI.
@@ -31,13 +31,16 @@ run-name: Determine which files have been changed
 
 on:
   workflow_call:
+    # N.B.: GitHub Actions workflow_call output values are ALWAYS strings, even
+    # for (what you think are) Booleans. Consequently, calling workflows have to
+    # test values using, e.g., ${{foo = 'false'}}, and not ${{foo}} or similar.
     outputs:
       code:
-        description: 'True if any code files were changed'
-        value: jobs.test.outputs.only-noncode-changes == 'false'
+        description: 'True if any potential code file was changed'
+        value: ${{jobs.test.outputs.nondoc-file-changes == 'true'}}
       python:
-        description: 'True if Python files were changed'
-        value: jobs.test.outputs.have-python-changes == 'true'
+        description: 'True if any Python file was changed'
+        value: ${{jobs.test.outputs.python-changes == 'true'}}
 
 permissions: read-all
 
@@ -47,24 +50,34 @@ jobs:
     runs-on: ubuntu-24.04
     timeout-minutes: 5
     outputs:
-      only-noncode-changes: steps.only-noncode-files.outputs.matched
-      python-changes: steps.python-files.outputs.matched
+      nondoc-file-changes: ${{steps.nondoc-files.outputs.matched}}
+      python-changes: ${{steps.python-files.outputs.matched}}
     steps:
       - name: Check out a copy of the git repository
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
 
-      - name: Test whether only docs or similar files were changed
+      - name: Test whether the changes involved one or more non-doc files
         uses: tomi/paths-filter-action@32c62f5ca100c1110406e3477d5b3ecef4666fec # v3.0.2
-        id: only-noncode-files
+        id: nondoc-files
         with:
           base: ${{github.ref_name}}
-          predicate-quantifier: 'every'
+          # Note: when editing the patterns below, always make sure to negate
+          # the condition (i.e., use a leading '!'). See the next comment.
           filters: |
             matched:
-              - '!**/*.md'
-              - '!docs/**'
               - '!.github/ISSUE_TEMPLATE/**'
+              - '!.github/dependabot.yaml'
+              - '!.github/problem-matchers/**'
               - '!CITATION.cff'
+              - '!docs/**'
+              - '!**/*.md'
+              - '!**/*.png'
+          # The default paths-filter-action behavior is "match at least one"
+          # pattern. We change the behavior to be "match every" pattern.
+          # Combined with negating every pattern above, it means the final output
+          # will be non-empty only if there is at least one file that is NOT a
+          # documentation file, or in other words, is a potential code file.
+          predicate-quantifier: 'every'
 
       - name: Test whether Python files are among the changed files
         uses: tomi/paths-filter-action@32c62f5ca100c1110406e3477d5b3ecef4666fec # v3.0.2
@@ -74,3 +87,9 @@ jobs:
           filters: |
             matched:
               - '**/*.py'
+
+      - name: Summary of test results
+        run: |
+          set -x
+          echo steps.nondoc-files.outputs.matched = │${{steps.nondoc-files.outputs.matched}}│
+          echo steps.python-files.outputs.matched = │${{steps.python-files.outputs.matched}}│
diff --git a/.github/workflows/ci_build_library.yaml b/.github/workflows/ci_build_library.yaml
index ae5006219..06774c321 100644
--- a/.github/workflows/ci_build_library.yaml
+++ b/.github/workflows/ci_build_library.yaml
@@ -45,12 +45,14 @@ concurrency:
 jobs:
   find-changes:
     name: Find changed files
-    uses: ./.github/workflows/reusable_find_changes.yaml
+    uses: ./.github/workflows/_find_changes.yaml
     secrets: inherit
 
   build-wheels:
     # For efficiency, skip this workflow if there were no code file changes.
-    if: needs.find-changes.outputs.code || github.event_name == 'workflow_dispatch'
+    if: >-
+      ${{needs.find-changes.outputs.code == 'true'
+         || github.event_name == 'workflow_dispatch'}}
     name: ${{matrix.conf.os}}/${{matrix.conf.pyarch}}/py3${{matrix.conf.py}}
     needs: find-changes
     runs-on: ${{matrix.conf.os}}
@@ -121,7 +123,7 @@ jobs:
       - if: matrix.conf.os != 'windows-2025'
         name: Run the build and test script (non-Windows case)
         env:
-          # SHELLOPTS is used by Bash. Add xtrace when doing manual debug runs.
+      # Add xtrace to SHELLOPTS for all Bash scripts when doing debug runs.
           SHELLOPTS: ${{inputs.debug && 'xtrace' || '' }}
         run: dev_tools/test_libs.sh ${{env.use-verbose && '--config=verbose'}}
 
diff --git a/.github/workflows/ci_build_wheels.yaml b/.github/workflows/ci_build_wheels.yaml
index 205d4be18..83c0d3a33 100644
--- a/.github/workflows/ci_build_wheels.yaml
+++ b/.github/workflows/ci_build_wheels.yaml
@@ -45,15 +45,17 @@ concurrency:
 jobs:
   find-changes:
     name: Find changed files
-    uses: ./.github/workflows/reusable_find_changes.yaml
+    uses: ./.github/workflows/_find_changes.yaml
     secrets: inherit
 
   build-wheels:
     # For efficiency, skip this workflow if there were no code file changes.
-    if: needs.find-changes.outputs.code || github.event_name == 'workflow_dispatch'
+    if: >-
+      ${{needs.find-changes.outputs.code == 'true'
+         || github.event_name == 'workflow_dispatch'}}
     name: Build & test wheels
     needs: find-changes
-    uses: ./.github/workflows/reusable_build_wheels.yaml
+    uses: ./.github/workflows/_build_wheels.yaml
     secrets: inherit
     with:
       debug: ${{inputs.debug == true}}
diff --git a/.github/workflows/ci_docker_tests.yaml b/.github/workflows/ci_docker_tests.yaml
index 77bf452c4..79de56871 100644
--- a/.github/workflows/ci_docker_tests.yaml
+++ b/.github/workflows/ci_docker_tests.yaml
@@ -45,12 +45,14 @@ concurrency:
 jobs:
   find-changes:
     name: Find changed files
-    uses: ./.github/workflows/reusable_find_changes.yaml
+    uses: ./.github/workflows/_find_changes.yaml
     secrets: inherit
 
   build-and-test:
     # For efficiency, skip this workflow if there were no code file changes.
-    if: needs.find-changes.outputs.code || github.event_name == 'workflow_dispatch'
+    if: >-
+      ${{needs.find-changes.outputs.code == 'true'
+         || github.event_name == 'workflow_dispatch'}}
     name: Build and test Docker images
     needs: find-changes
     runs-on: ubuntu-24.04
diff --git a/.github/workflows/ci_format_checks.yml b/.github/workflows/ci_format_checks.yml
index 820a39a49..d52e78648 100644
--- a/.github/workflows/ci_format_checks.yml
+++ b/.github/workflows/ci_format_checks.yml
@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-name: 'CI: lint & format checks'
+name: 'CI: check code format'
 run-name: Test with linters and formatters
 
 on:
@@ -45,16 +45,21 @@ concurrency:
 jobs:
   find-changes:
     name: Find changed files
-    uses: ./.github/workflows/reusable_find_changes.yaml
+    uses: ./.github/workflows/_find_changes.yaml
     secrets: inherit
 
   check-format:
     # For efficiency, skip this workflow if there were no Python file changes.
-    if: needs.find-changes.outputs.python || github.event_name == 'workflow_dispatch'
+    if: >-
+      ${{needs.find-changes.outputs.python == 'true'
+         || github.event_name == 'workflow_dispatch'}}
     name: Python format check
     needs: find-changes
     runs-on: ubuntu-24.04
     timeout-minutes: 30
+    env:
+      # Add xtrace to SHELLOPTS for all Bash scripts when doing debug runs.
+      SHELLOPTS: ${{inputs.debug && 'xtrace' || '' }}
     steps:
       - name: Check out a copy of the git repository
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
@@ -77,7 +82,4 @@ jobs:
           pip install -r dev-requirements.txt
 
       - name: Check Python file format
-        env:
-          # SHELLOPTS is used by Bash. Add xtrace when doing manual debug runs.
-          SHELLOPTS: ${{inputs.debug && 'xtrace' || '' }}
         run: check/format-incremental
diff --git a/.github/workflows/ci_hardware_options.yaml b/.github/workflows/ci_hardware_options.yaml
index dbea2d0ee..e2cc83976 100644
--- a/.github/workflows/ci_hardware_options.yaml
+++ b/.github/workflows/ci_hardware_options.yaml
@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-name: 'CI: hardware options tests'
+name: 'CI: test with different hardware options'
 run-name: Test with instruction set extensions and parallelism
 
 on:
@@ -45,12 +45,14 @@ concurrency:
 jobs:
   find-changes:
     name: Find changed files
-    uses: ./.github/workflows/reusable_find_changes.yaml
+    uses: ./.github/workflows/_find_changes.yaml
     secrets: inherit
 
   test-options:
     # For efficiency, skip this workflow if there were no code file changes.
-    if: needs.find-changes.outputs.code || github.event_name == 'workflow_dispatch'
+    if: >-
+      ${{needs.find-changes.outputs.code == 'true'
+         || github.event_name == 'workflow_dispatch'}}
     name: Test ${{matrix.hardware_opt}} + ${{matrix.parallel_opt}}
     needs: find-changes
     runs-on: ubuntu-24.04
diff --git a/.github/workflows/ci_sanitizer_tests.yaml b/.github/workflows/ci_sanitizer_tests.yaml
index 8ec0c982f..0bc2383f7 100644
--- a/.github/workflows/ci_sanitizer_tests.yaml
+++ b/.github/workflows/ci_sanitizer_tests.yaml
@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-name: 'CI: sanitizer tests'
+name: 'CI: run sanitizer tests'
 run-name: Test with address and memory sanitizers
 
 on:
@@ -45,12 +45,14 @@ concurrency:
 jobs:
   find-changes:
     name: Find changed files
-    uses: ./.github/workflows/reusable_find_changes.yaml
+    uses: ./.github/workflows/_find_changes.yaml
     secrets: inherit
 
   sanitizer-tests:
     # For efficiency, skip this workflow if there were no code file changes.
-    if: needs.find-changes.outputs.code || github.event_name == 'workflow_dispatch'
+    if: >-
+      ${{needs.find-changes.outputs.code == 'true'
+         || github.event_name == 'workflow_dispatch'}}
     name: Test with sanitizers
     needs: find-changes
     runs-on: ubuntu-24.04
diff --git a/.github/workflows/ci_tcmalloc_test.yaml b/.github/workflows/ci_tcmalloc_test.yaml
index 8998a5060..3090a43d2 100644
--- a/.github/workflows/ci_tcmalloc_test.yaml
+++ b/.github/workflows/ci_tcmalloc_test.yaml
@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-name: 'CI: TCMalloc test'
+name: 'CI: run TCMalloc test'
 run-name: Test with TCMalloc (thread-caching malloc)
 
 on:
@@ -45,12 +45,14 @@ concurrency:
 jobs:
   find-changes:
     name: Find changed files
-    uses: ./.github/workflows/reusable_find_changes.yaml
+    uses: ./.github/workflows/_find_changes.yaml
     secrets: inherit
 
   tcmalloc-test:
     # For efficiency, skip this workflow if there were no code file changes.
-    if: needs.find-changes.outputs.code || github.event_name == 'workflow_dispatch'
+    if: >-
+      ${{needs.find-changes.outputs.code == 'true'
+         || github.event_name == 'workflow_dispatch'}}
     name: Test with TCMalloc
     needs: find-changes
     runs-on: ubuntu-24.04
diff --git a/.github/workflows/pr-labeler.yaml b/.github/workflows/pr-labeler.yaml
index 13b865a2c..2d3424634 100644
--- a/.github/workflows/pr-labeler.yaml
+++ b/.github/workflows/pr-labeler.yaml
@@ -19,7 +19,7 @@
 # getting applied, check the run summary page for errors.
 # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-name: Pull request labeler
+name: Label pull requests
 run-name: >-
   Label pull request ${{github.event.pull_request.number}} by ${{github.actor}}
 
diff --git a/.github/workflows/release_wheels.yml b/.github/workflows/release_wheels.yml
index 68eb5fa53..7f3f7ca43 100644
--- a/.github/workflows/release_wheels.yml
+++ b/.github/workflows/release_wheels.yml
@@ -31,7 +31,7 @@ permissions: read-all
 jobs:
   build-wheels:
     name: Build and save wheels
-    uses: ./.github/workflows/reusable_build_wheels.yaml
+    uses: ./.github/workflows/_build_wheels.yaml
     secrets: inherit
     with:
       upload: true