diff --git a/.github/workflows/actionlint.yml b/.github/workflows/actionlint.yml
new file mode 100644
index 0000000000..7c84f7da4f
--- /dev/null
+++ b/.github/workflows/actionlint.yml
@@ -0,0 +1,21 @@
+---
+name: actionlint
+'on':
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+jobs:
+  actionlint:
+    runs-on: ubuntu-22.04
+    steps:
+      - uses: actions/checkout@v4
+      - name: Download actionlint
+        id: get_actionlint
+        run: bash <(curl https://raw.githubusercontent.com/rhysd/actionlint/main/scripts/download-actionlint.bash)
+        shell: bash
+      - name: Check workflow files
+        run: ${{ steps.get_actionlint.outputs.executable }} -color
+        shell: bash
diff --git a/.github/workflows/codecov.yml b/.github/workflows/codecov.yml
index adee863282..99d67255cf 100644
--- a/.github/workflows/codecov.yml
+++ b/.github/workflows/codecov.yml
@@ -16,7 +16,7 @@ jobs:
   codecov:
     runs-on: ubuntu-22.04
     steps:
-      - uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b # v4
+      - uses: actions/checkout@v4
       - uses: teatimeguest/setup-texlive-action@v3.2.1
         with:
           update-all-packages: true
diff --git a/.github/workflows/daily.yml b/.github/workflows/daily.yml
index 20d1e638f7..7c18d12027 100644
--- a/.github/workflows/daily.yml
+++ b/.github/workflows/daily.yml
@@ -8,23 +8,27 @@ jobs:
   build:
     runs-on: ubuntu-22.04
     steps:
-      - uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b # v4
+      - uses: actions/checkout@v4
       - uses: teatimeguest/setup-texlive-action@v3.2.1
         with:
           update-all-packages: true
           packages: scheme-basic geometry xcolor naive-ebnf microtype etoolbox
+      - uses: actions/setup-java@v4
+        with:
+          distribution: 'temurin'
+          java-version: 20
       - uses: actions/cache@v4
         with:
           path: ~/.m2/repository
-          key: ${{ runner.os }}-jdk-${{ matrix.java }}-maven-${{ hashFiles('**/pom.xml') }}
+          key: ${{ runner.os }}-jdk-20-maven-${{ hashFiles('**/pom.xml') }}
           restore-keys: |
-            ${{ runner.os }}-jdk-${{ matrix.java }}-maven-
+            ${{ runner.os }}-jdk-20-maven-
       - run: |
           # Clean the test classes to avoid caching issues and prepare testing environment
           # without running the tests
           mvn clean install -Pqulice -DskipTests -DskipITs -Dinvoker.skip=true
           # Find script
-          SCRIPT="${GITHUB_WORKSPACE}/src/test/scripts/test-repetition.sh"
+          SCRIPT=${GITHUB_WORKSPACE}/src/test/scripts/test-repetition.sh
           # Check that script is exists
           if [ ! -f "${SCRIPT}" ]; then
               echo "Script ${SCRIPT} not found"
@@ -33,15 +37,15 @@ jobs:
           # Make script runnable
           chmod +x "${SCRIPT}"
           # Test eo-parser
-          ${SCRIPT} --max 10 --folder ${GITHUB_WORKSPACE}/eo-parser
+          "${SCRIPT}" --max 10 --folder "${GITHUB_WORKSPACE}/eo-parser"
           # Test eo-maven-plugin
-          ${SCRIPT} --max 10 --folder ${GITHUB_WORKSPACE}/eo-maven-plugin
+          "${SCRIPT}" --max 10 --folder "${GITHUB_WORKSPACE}/eo-maven-plugin"
           # Test eo-runtime
-          ${SCRIPT} --max 10 --folder ${GITHUB_WORKSPACE}/eo-runtime --compilation true
+          "${SCRIPT}" --max 10 --folder "${GITHUB_WORKSPACE}/eo-runtime" --compilation true
   report-fail:
     name: Create issue on failure
     needs: build
-    if: failure() && github.even.pull_request == null
+    if: failure() && github.event.pull_request == null
     runs-on: ubuntu-22.04
     steps:
       - uses: jayqi/failed-build-issue-action@v1
diff --git a/.github/workflows/ebnf.yml b/.github/workflows/ebnf.yml
index 34b9fac415..0a3f846626 100644
--- a/.github/workflows/ebnf.yml
+++ b/.github/workflows/ebnf.yml
@@ -13,7 +13,7 @@ jobs:
     env:
       CONVERT_PATH: /tmp/antlr4-to-bnf-converter
     steps:
-      - uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b # v4
+      - uses: actions/checkout@v4
       - run: |
           sudo apt-get update
           sudo apt-get -y install ghostscript imagemagick texlive-extra-utils pdf2svg inkscape
@@ -28,8 +28,8 @@ jobs:
       - uses: actions/cache@v4
         with:
           path: ~/.m2/repository
-          key: ${{ runner.os }}-jdk-${{ matrix.java }}-maven-${{ hashFiles('**/pom.xml') }}
-          restore-keys: ${{ runner.os }}-jdk-${{ matrix.java }}-maven-
+          key: ${{ runner.os }}-jdk-20-maven-${{ hashFiles('**/pom.xml') }}
+          restore-keys: ${{ runner.os }}-jdk-20-maven-
       - run: |
           mkdir -p "$CONVERT_PATH"
           wget --quiet http://public.yegor256.com/convert.zip -O /tmp/convert.zip
diff --git a/.github/workflows/gpt-code-review.yml b/.github/workflows/gpt-code-review.yml
index e19e1effff..683f91dc6b 100644
--- a/.github/workflows/gpt-code-review.yml
+++ b/.github/workflows/gpt-code-review.yml
@@ -10,7 +10,7 @@ jobs:
   build:
     runs-on: ubuntu-22.04
     steps:
-      - uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b # v4
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 0
       - uses: actions/setup-node@v4
diff --git a/.github/workflows/loc-badge.yml b/.github/workflows/loc-badge.yml
index c2b68fdbe9..a068afd74d 100644
--- a/.github/workflows/loc-badge.yml
+++ b/.github/workflows/loc-badge.yml
@@ -11,7 +11,7 @@ jobs:
   loc-badge:
     runs-on: ubuntu-22.04
     steps:
-      - uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b # v4
+      - uses: actions/checkout@v4
       - uses: shadowmoose/GHA-LoC-Badge@1.0.0
         with:
           debug: true
diff --git a/.github/workflows/markdown-lint.yml b/.github/workflows/markdown-lint.yml
index 62b9aac4f3..a11dbe4fcf 100644
--- a/.github/workflows/markdown-lint.yml
+++ b/.github/workflows/markdown-lint.yml
@@ -1,6 +1,6 @@
 ---
 name: markdown-lint
-on:
+'on':
   push:
     branches:
       - master
@@ -8,12 +8,9 @@ on:
     branches:
       - master
     paths-ignore: [ 'paper/**', 'sandbox/**' ]
-concurrency:
-  group: markdown-lint-${{ github.ref }}
-  cancel-in-progress: true
 jobs:
   markdown-lint:
     runs-on: ubuntu-22.04
     steps:
-      - uses: actions/checkout@8459bc0c7e3759cdf591f513d9f141a95fef0a8f
+      - uses: actions/checkout@v4
       - uses: articulate/actions-markdownlint@v1
diff --git a/.github/workflows/simian.yml b/.github/workflows/simian.yml
index 0aaee3bc75..216adc49cb 100644
--- a/.github/workflows/simian.yml
+++ b/.github/workflows/simian.yml
@@ -16,12 +16,10 @@ jobs:
   simian:
     runs-on: ubuntu-22.04
     steps:
-      - uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b # v4
+      - uses: actions/checkout@v4
       - uses: actions/setup-java@v4
         with:
           distribution: 'temurin'
           java-version: 17
-      - run: |
-          wget --quiet http://public.yegor256.com/simian.jar -O /tmp/simian.jar
-      - run: |
-          java -jar /tmp/simian.jar -threshold=19 -excludes=**/gen -excludes=**/it **/*.java
+      - run: wget --quiet http://public.yegor256.com/simian.jar -O /tmp/simian.jar
+      - run: java -jar /tmp/simian.jar -threshold=19 "-excludes=**/gen" "-excludes=**/it" "**/*.java"
diff --git a/.github/workflows/sonar.yml b/.github/workflows/sonar.yml
index 3f1747d484..ff53f9c536 100644
--- a/.github/workflows/sonar.yml
+++ b/.github/workflows/sonar.yml
@@ -11,7 +11,7 @@ jobs:
   sonar:
     runs-on: ubuntu-22.04
     steps:
-      - uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b # v4
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 0
       - uses: teatimeguest/setup-texlive-action@v3.2.1
diff --git a/.github/workflows/typos.yml b/.github/workflows/typos.yml
new file mode 100644
index 0000000000..74c330cbb6
--- /dev/null
+++ b/.github/workflows/typos.yml
@@ -0,0 +1,16 @@
+---
+
+name: typos
+'on':
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+jobs:
+  typos:
+    runs-on: ubuntu-22.04
+    steps:
+      - uses: actions/checkout@v4
+      - uses: crate-ci/typos@master
diff --git a/.github/workflows/up.yml b/.github/workflows/up.yml
index fd7ec0b84f..3463a54a07 100644
--- a/.github/workflows/up.yml
+++ b/.github/workflows/up.yml
@@ -13,7 +13,7 @@ jobs:
   up:
     runs-on: ubuntu-22.04
     steps:
-      - uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b # v4
+      - uses: actions/checkout@v4
       - run: |-
           git fetch --tags --force && \
           latest=$(git tag --sort=creatordate | tail -1) && \
diff --git a/.github/workflows/xcop.yml b/.github/workflows/xcop.yml
index 225b4377be..c0ab79a52c 100644
--- a/.github/workflows/xcop.yml
+++ b/.github/workflows/xcop.yml
@@ -14,7 +14,7 @@ jobs:
   xcop:
     runs-on: ubuntu-22.04
     steps:
-      - uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b # v4
+      - uses: actions/checkout@v4
       - uses: g4s8/xcop-action@v1.3
         with:
           files: |
diff --git a/.github/workflows/year.yml b/.github/workflows/year.yml
index 86b3f80047..8415773d52 100644
--- a/.github/workflows/year.yml
+++ b/.github/workflows/year.yml
@@ -10,7 +10,7 @@ jobs:
   license:
     runs-on: ubuntu-22.04
     steps:
-      - uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b # v4
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 0
       - uses: FantasticFiasco/action-update-license-year@v3
diff --git a/_typos.toml b/_typos.toml
new file mode 100644
index 0000000000..28589a6135
--- /dev/null
+++ b/_typos.toml
@@ -0,0 +1,14 @@
+[default]
+extend-ignore-identifiers-re = [
+  "Olt*",       # false positive
+  "Onot",       # false positive
+  "BA",         # false positive
+  "thi",        # false positive
+  "lowcase",    # false positive
+  "[D,d]atas*", # valid variable names
+  "thr",        # valid variable name
+  "cutted",     # valid variable name
+  "splitted",   # valid variable name
+  "scrpt",      # valid variable name
+  "fle"         # valid variable name
+]
diff --git a/eo-maven-plugin/src/main/java/org/eolang/maven/PhiMojo.java b/eo-maven-plugin/src/main/java/org/eolang/maven/PhiMojo.java
index 7e4f7d0e98..639ba36302 100644
--- a/eo-maven-plugin/src/main/java/org/eolang/maven/PhiMojo.java
+++ b/eo-maven-plugin/src/main/java/org/eolang/maven/PhiMojo.java
@@ -167,7 +167,7 @@ count, new Rel(this.phiInputDir), new Rel(this.phiOutputDir)
 
     /**
      * Translate given xmir to phi calculus expression.
-     * @param train Train that optimize and traslates given xmir
+     * @param train Train that optimize and translates given xmir
      * @param xmir Text of xmir
      * @return Translated xmir
      * @throws ImpossibleToPhiTranslationException If fails to translate given XMIR to phi
diff --git a/eo-maven-plugin/src/main/java/org/eolang/maven/hash/ChRemote.java b/eo-maven-plugin/src/main/java/org/eolang/maven/hash/ChRemote.java
index 8561f5760e..fbe1393a2b 100644
--- a/eo-maven-plugin/src/main/java/org/eolang/maven/hash/ChRemote.java
+++ b/eo-maven-plugin/src/main/java/org/eolang/maven/hash/ChRemote.java
@@ -25,7 +25,6 @@
 
 import com.jcabi.log.Logger;
 import org.cactoos.Text;
-import org.cactoos.text.Sticky;
 
 /**
  * Hash of tag from objectionary.
@@ -37,7 +36,7 @@ public final class ChRemote implements CommitHash {
     /**
      * Cached text of hashes.
      */
-    private static final Text CACHE = new Sticky(new CommitHashesText());
+    private static final Text CACHE = new CommitHashesText();
 
     /**
      * Tag.
diff --git a/eo-maven-plugin/src/main/java/org/eolang/maven/hash/CommitHash.java b/eo-maven-plugin/src/main/java/org/eolang/maven/hash/CommitHash.java
index 53043dd03e..9491b1d79e 100644
--- a/eo-maven-plugin/src/main/java/org/eolang/maven/hash/CommitHash.java
+++ b/eo-maven-plugin/src/main/java/org/eolang/maven/hash/CommitHash.java
@@ -23,12 +23,15 @@
  */
 package org.eolang.maven.hash;
 
+import org.cactoos.Scalar;
+
 /**
  * Hash of tag.
  *
  * @since 0.28.11
  */
-public interface CommitHash {
+@FunctionalInterface
+public interface CommitHash extends Scalar<String> {
 
     /**
      * SHA Hash.
diff --git a/eo-maven-plugin/src/test/java/org/eolang/maven/PrintMojoTest.java b/eo-maven-plugin/src/test/java/org/eolang/maven/PrintMojoTest.java
index 19675809cf..05678f6ee3 100644
--- a/eo-maven-plugin/src/test/java/org/eolang/maven/PrintMojoTest.java
+++ b/eo-maven-plugin/src/test/java/org/eolang/maven/PrintMojoTest.java
@@ -95,7 +95,7 @@ void printsInStraightNotation(final String pack, @TempDir final Path temp) throw
     void printsInReversedNotation(final String pack, @TempDir final Path temp) throws Exception {
         final Map<String, Object> yaml = new Yaml().load(pack);
         MatcherAssert.assertThat(
-            "PrintMojo should print EO in reveresed notation, but it didn't",
+            "PrintMojo should print EO in reversed notation, but it didn't",
             PrintMojoTest.printed(yaml, temp, true).asString(),
             Matchers.equalTo((String) yaml.get("reversed"))
         );
diff --git a/eo-maven-plugin/src/test/java/org/eolang/maven/VerifyMojoTest.java b/eo-maven-plugin/src/test/java/org/eolang/maven/VerifyMojoTest.java
index a4caff7ff3..e13694abed 100644
--- a/eo-maven-plugin/src/test/java/org/eolang/maven/VerifyMojoTest.java
+++ b/eo-maven-plugin/src/test/java/org/eolang/maven/VerifyMojoTest.java
@@ -251,7 +251,7 @@ void failsOnWarning(@TempDir final Path temp) throws Exception {
     /**
      * Apply XSL transformation.
      * @param xsl Path to XSL within classpath
-     * @param xml Path to XML to be tranformed
+     * @param xml Path to XML to be transformed
      */
     private static void applyXsl(final String xsl, final Path xml) throws Exception {
         final XML output = new Xsline(
diff --git a/eo-maven-plugin/src/test/java/org/eolang/maven/hash/ChRemoteTest.java b/eo-maven-plugin/src/test/java/org/eolang/maven/hash/ChRemoteTest.java
index 7e3c048a9d..67d6c38c8f 100644
--- a/eo-maven-plugin/src/test/java/org/eolang/maven/hash/ChRemoteTest.java
+++ b/eo-maven-plugin/src/test/java/org/eolang/maven/hash/ChRemoteTest.java
@@ -25,6 +25,10 @@
 package org.eolang.maven.hash;
 
 import com.yegor256.WeAreOnline;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
+import org.cactoos.experimental.Threads;
 import org.eolang.maven.BinarizeParseTest;
 import org.hamcrest.MatcherAssert;
 import org.hamcrest.Matchers;
@@ -67,4 +71,22 @@ void throwsCommitHashException() {
             BinarizeParseTest.TO_ADD_MESSAGE
         );
     }
+
+    @Test
+    void isThreadSafe() {
+        final int threads = 200;
+        final String sample = new ChRemote("0.23.19").value();
+        MatcherAssert.assertThat(
+            "You can use this class concurrently",
+            StreamSupport.stream(
+                new Threads<>(
+                    threads,
+                    Stream.generate(
+                        () -> new ChRemote("0.23.19")
+                    ).limit(threads).collect(Collectors.toList())
+                ).spliterator(), false
+            ).filter(str -> !sample.equals(str)).collect(Collectors.toList()),
+            Matchers.empty()
+        );
+    }
 }
diff --git a/eo-parser/src/main/antlr4/org/eolang/parser/Eo.g4 b/eo-parser/src/main/antlr4/org/eolang/parser/Eo.g4
index b3299864a0..be88cd0fbd 100644
--- a/eo-parser/src/main/antlr4/org/eolang/parser/Eo.g4
+++ b/eo-parser/src/main/antlr4/org/eolang/parser/Eo.g4
@@ -275,7 +275,7 @@ vapplicationArgUnboundCurrent
 vapplicationArgUnboundNext
     : vapplicationArgVanonymUnbound // vertical anonym object
     | vapplicationHeadNamed vapplicationArgs // vertical application
-    | reversed oname? vapplicationArgsReversed // reversed verical application
+    | reversed oname? vapplicationArgsReversed // reversed vertical application
     ;
 
 // Horizontal application as argument of vertical application
@@ -351,7 +351,7 @@ onlyphiTail: spacedArrow attributes
     ;
 
 // Inner object of horizontal anonym object
-// Does not contan elements in vertical notation
+// Does not contain elements in vertical notation
 hanonymInner
     : SPACE LB (hmethod | hmethodVersioned | happlication | hanonym | just) oname RB
     ;
@@ -390,7 +390,7 @@ hmethodExtended
 // The whole method is written in one line
 // The head does not contain elements in vertical notation
 // The division of elements into regular and versioned ones is due to
-// the presence of horizontal application where head or agruments can't
+// the presence of horizontal application where head or arguments can't
 // contain version
 hmethodVersioned
     : hmethodHead methodTail* methodTailVersioned
diff --git a/eo-parser/src/main/java/org/eolang/parser/Objects.java b/eo-parser/src/main/java/org/eolang/parser/Objects.java
index cc123898b9..50053ca082 100644
--- a/eo-parser/src/main/java/org/eolang/parser/Objects.java
+++ b/eo-parser/src/main/java/org/eolang/parser/Objects.java
@@ -63,7 +63,7 @@ interface Objects extends Iterable<Directive> {
     Objects prop(String key, Object value);
 
     /**
-     * Empty propery.
+     * Empty property.
      * @param key Key.
      * @return Self.
      */
diff --git a/eo-parser/src/test/resources/org/eolang/parser/typos/redundent-parenheses.yaml b/eo-parser/src/test/resources/org/eolang/parser/typos/redundant-parenheses.yaml
similarity index 100%
rename from eo-parser/src/test/resources/org/eolang/parser/typos/redundent-parenheses.yaml
rename to eo-parser/src/test/resources/org/eolang/parser/typos/redundant-parenheses.yaml
diff --git a/eo-runtime/src/main/java/EOorg/EOeolang/Cages.java b/eo-runtime/src/main/java/EOorg/EOeolang/Cages.java
index da4b9ef117..16567cdde4 100644
--- a/eo-runtime/src/main/java/EOorg/EOeolang/Cages.java
+++ b/eo-runtime/src/main/java/EOorg/EOeolang/Cages.java
@@ -58,7 +58,7 @@ private Cages() {
     /**
      * Encage object for the first time.
      * When object is encaged - locator will be generated.
-     * @param object Object ot encage
+     * @param object Object to encage
      * @return Locator to the object in cage
      */
     int init(final Phi object) {
diff --git a/eo-runtime/src/test/eo/org/eolang/bytes-tests.eo b/eo-runtime/src/test/eo/org/eolang/bytes-tests.eo
index 5ed5c9bf3e..54c5bf7574 100644
--- a/eo-runtime/src/test/eo/org/eolang/bytes-tests.eo
+++ b/eo-runtime/src/test/eo/org/eolang/bytes-tests.eo
@@ -261,7 +261,7 @@
       53.as-bytes.not
 
 # Test.
-[] > conjuction-of-bytes
+[] > conjunction-of-bytes
   02-EF-D4-05-5E-78-3A > a
   12-33-C1-B5-5E-71-55 > b
   eq. > @
@@ -286,7 +286,7 @@
     1
 
 # Test.
-[] > convertable-to-bool
+[] > convertible-to-bool
   not. > @
     eq.
       01-.as-bool
diff --git a/eo-runtime/src/test/eo/org/eolang/seq-tests.eo b/eo-runtime/src/test/eo/org/eolang/seq-tests.eo
index 8c3488ab17..bbcc3e4147 100644
--- a/eo-runtime/src/test/eo/org/eolang/seq-tests.eo
+++ b/eo-runtime/src/test/eo/org/eolang/seq-tests.eo
@@ -12,7 +12,7 @@
 # The above copyright notice and this permission notice shall be included
 # in all copies or substantial portions of the Software.
 #
-# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EcounterPRESS OR
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 # FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
 # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
diff --git a/eo-runtime/src/test/java/EOorg/EOeolang/EOmallocTest.java b/eo-runtime/src/test/java/EOorg/EOeolang/EOmallocTest.java
index 223c1179e0..ff561d58b1 100644
--- a/eo-runtime/src/test/java/EOorg/EOeolang/EOmallocTest.java
+++ b/eo-runtime/src/test/java/EOorg/EOeolang/EOmallocTest.java
@@ -63,7 +63,7 @@ void freesMemory() {
     }
 
     @Test
-    void freesMemoryIfErrorIsOccured() {
+    void freesMemoryIfErrorIsOccurred() {
         final ErrorDummy dummy = new ErrorDummy();
         final Phi phi = EOmallocTest.allocated(
             new Data.ToPhi(1L),