diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 0926a04526..b942864322 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -1,10 +1,10 @@
-on:
+'on':
   push:
     paths-ignore:
-      - 'tutorials/**'
+      - tutorials/**
     branches:
-    - main
-  pull_request:
+      - 3.15.x
+  pull_request: null
 name: ci
 jobs:
   units:
@@ -12,68 +12,71 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        java: [11, 17, 21]
+        java:
+          - 11
+          - 17
+          - 21
     steps:
-    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
-    - uses: actions/setup-java@v2
-      with:
-        distribution: temurin
-        java-version: ${{matrix.java}}
-    - run: java -version
-    - run: .kokoro/build.sh
-      env:
-        JOB_TYPE: test
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
+      - uses: actions/setup-java@v2
+        with:
+          distribution: temurin
+          java-version: ${{matrix.java}}
+      - run: java -version
+      - run: .kokoro/build.sh
+        env:
+          JOB_TYPE: test
   units-java8:
-    # Building using Java 17 and run the tests with Java 8 runtime
-    name: "units (8)"
+    name: units (8)
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
-    - uses: actions/setup-java@v3
-      with:
-        java-version: 8
-        distribution: zulu
-    - name: "Set jvm system property environment variable for surefire plugin (unit tests)"
-      # Maven surefire plugin (unit tests) allows us to specify JVM to run the tests.
-      # https://maven.apache.org/surefire/maven-surefire-plugin/test-mojo.html#jvm
-      run: echo "SUREFIRE_JVM_OPT=-Djvm=${JAVA_HOME}/bin/java" >> $GITHUB_ENV
-      shell: bash
-    - uses: actions/setup-java@v3
-      with:
-        java-version: 17
-        distribution: zulu
-    - run: .kokoro/build.sh
-      env:
-        JOB_TYPE: test
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
+      - uses: actions/setup-java@v3
+        with:
+          java-version: 8
+          distribution: zulu
+      - name: >-
+          Set jvm system property environment variable for surefire plugin (unit
+          tests)
+        run: echo "SUREFIRE_JVM_OPT=-Djvm=${JAVA_HOME}/bin/java" >> $GITHUB_ENV
+        shell: bash
+      - uses: actions/setup-java@v3
+        with:
+          java-version: 17
+          distribution: zulu
+      - run: .kokoro/build.sh
+        env:
+          JOB_TYPE: test
   windows:
     runs-on: windows-latest
     steps:
-    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
-    - uses: actions/setup-java@v2
-      with:
-        distribution: temurin
-        java-version: 8
-    - run: java -version
-    - run: .kokoro/build.bat
-      env:
-        JOB_TYPE: test
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
+      - uses: actions/setup-java@v2
+        with:
+          distribution: temurin
+          java-version: 8
+      - run: java -version
+      - run: .kokoro/build.bat
+        env:
+          JOB_TYPE: test
   dependencies:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [17]
+        java:
+          - 17
     steps:
-    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
-    - uses: actions/setup-java@v2
-      with:
-        distribution: temurin
-        java-version: ${{matrix.java}}
-    - run: java -version
-    - run: .kokoro/dependencies.sh
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
+      - uses: actions/setup-java@v2
+        with:
+          distribution: temurin
+          java-version: ${{matrix.java}}
+      - run: java -version
+      - run: .kokoro/dependencies.sh
   javadoc:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
       - uses: actions/setup-java@v3
         with:
           distribution: temurin
@@ -85,24 +88,24 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
-    - uses: actions/setup-java@v2
-      with:
-        distribution: temurin
-        java-version: 17
-    - run: java -version
-    - run: .kokoro/build.sh
-      env:
-        JOB_TYPE: lint
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
+      - uses: actions/setup-java@v2
+        with:
+          distribution: temurin
+          java-version: 17
+      - run: java -version
+      - run: .kokoro/build.sh
+        env:
+          JOB_TYPE: lint
   clirr:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
-    - uses: actions/setup-java@v2
-      with:
-        distribution: temurin
-        java-version: 8
-    - run: java -version
-    - run: .kokoro/build.sh
-      env:
-        JOB_TYPE: clirr
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
+      - uses: actions/setup-java@v2
+        with:
+          distribution: temurin
+          java-version: 8
+      - run: java -version
+      - run: .kokoro/build.sh
+        env:
+          JOB_TYPE: clirr