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 ebf2d62364..fe425060bd 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
@@ -24,25 +24,29 @@
 package org.eolang.maven;
 
 import com.jcabi.log.Logger;
+import com.jcabi.xml.XML;
 import com.jcabi.xml.XMLDocument;
-import com.jcabi.xml.XSLDocument;
+import com.yegor256.xsline.Shift;
+import com.yegor256.xsline.StClasspath;
+import com.yegor256.xsline.TrDefault;
+import com.yegor256.xsline.Train;
+import com.yegor256.xsline.Xsline;
 import java.io.File;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import org.apache.maven.plugins.annotations.LifecyclePhase;
 import org.apache.maven.plugins.annotations.Mojo;
 import org.apache.maven.plugins.annotations.Parameter;
-import org.cactoos.Text;
 import org.cactoos.experimental.Threads;
-import org.cactoos.io.ResourceOf;
 import org.cactoos.iterable.Mapped;
 import org.cactoos.number.SumOf;
-import org.cactoos.text.Sticky;
 import org.cactoos.text.TextOf;
 import org.eolang.maven.util.HmBase;
 import org.eolang.maven.util.Home;
 import org.eolang.maven.util.Rel;
 import org.eolang.maven.util.Walk;
+import org.eolang.parser.ParsingTrain;
+import org.eolang.parser.Schema;
 
 /**
  * Read XMIR files and translate them to the phi-calculus expression.
@@ -59,15 +63,6 @@ public final class PhiMojo extends SafeMojo {
      */
     public static final String EXT = "phi";
 
-    /**
-     * Translation to phi.
-     */
-    private static final Text TRANSLATION = new Sticky(
-        new TextOf(
-            new ResourceOf("org/eolang/maven/phi/to-phi.xsl")
-        )
-    );
-
     /**
      * The directory where to take xmir files for translation from.
      * @checkstyle MemberNameCheck (10 lines)
@@ -90,21 +85,40 @@ public final class PhiMojo extends SafeMojo {
     )
     private File phiOutputDir;
 
+    /**
+     * Pass XMIR to Optimizations train or not.
+     * This flag is used for test in order not to optimize XMIR twice:
+     * in {@link OptimizeMojo} and here.
+     * @checkstyle MemberNameCheck (5 lines)
+     */
+    @SuppressWarnings("PMD.ImmutableField")
+    private boolean phiOptimize = true;
+
     @Override
     public void exec() {
         final Home home = new HmBase(this.phiOutputDir);
+        final Train<Shift> train;
+        if (this.phiOptimize) {
+            train = new ParsingTrain();
+        } else {
+            train = new TrDefault<>();
+        }
         final int count = new SumOf(
             new Threads<>(
                 Runtime.getRuntime().availableProcessors(),
                 new Mapped<>(
                     xmir -> () -> {
+                        final XML xml = new XMLDocument(
+                            new TextOf(xmir).asString()
+                        );
+                        new Schema(xml).check();
                         final Path relative = Paths.get(
                             this.phiInputDir.toPath().relativize(xmir).toString().replace(
                                 String.format(".%s", TranspileMojo.EXT),
                                 String.format(".%s", PhiMojo.EXT)
                             )
                         );
-                        home.save(PhiMojo.translated(new TextOf(xmir)), relative);
+                        home.save(PhiMojo.translated(train, xml), relative);
                         Logger.info(
                             this,
                             "Translated to phi: %s -> %s",
@@ -131,13 +145,16 @@ 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 xmir Text of xmir
      * @return Translated xmir
-     * @throws Exception If fail to translate
      */
-    private static String translated(final Text xmir) throws Exception {
-        return new XSLDocument(PhiMojo.TRANSLATION.asString()).applyTo(
-            new XMLDocument(xmir.asString())
-        );
+    private static String translated(final Train<Shift> train, final XML xmir) {
+        return new Xsline(
+            train.with(new StClasspath("/org/eolang/maven/phi/to-phi.xsl"))
+        )
+            .pass(xmir)
+            .xpath("phi/text()")
+            .get(0);
     }
 }
diff --git a/eo-maven-plugin/src/main/resources/org/eolang/maven/phi/to-phi.xsl b/eo-maven-plugin/src/main/resources/org/eolang/maven/phi/to-phi.xsl
index 77da717015..4002ef2855 100644
--- a/eo-maven-plugin/src/main/resources/org/eolang/maven/phi/to-phi.xsl
+++ b/eo-maven-plugin/src/main/resources/org/eolang/maven/phi/to-phi.xsl
@@ -24,6 +24,7 @@ SOFTWARE.
 -->
 <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:eo="https://www.eolang.org" id="to-phi" version="2.0">
   <xsl:output encoding="UTF-8" method="text"/>
+  <xsl:import href="/org/eolang/parser/_datas.xsl"/>
   <!-- Variables -->
   <xsl:variable name="aliases" select="program/metas/meta/part[last()]"/>
   <xsl:variable name="xi">
@@ -73,6 +74,7 @@ SOFTWARE.
     <select>∅</select>
   </xsl:variable>
   <!-- Functions -->
+  <!-- ADD XI OR NOT -->
   <xsl:function name="eo:add-xi">
     <xsl:param name="add"/>
     <xsl:if test="$add">
@@ -80,6 +82,7 @@ SOFTWARE.
       <xsl:text>.</xsl:text>
     </xsl:if>
   </xsl:function>
+  <!-- SPECIAL CHARACTERS -->
   <xsl:function name="eo:specials">
     <xsl:param name="n"/>
     <xsl:param name="is-name"/>
@@ -138,6 +141,7 @@ SOFTWARE.
       </xsl:otherwise>
     </xsl:choose>
   </xsl:function>
+  <!-- TOKENIZE BYTES -->
   <xsl:function name="eo:bytes">
     <xsl:param name="bts"/>
     <xsl:choose>
@@ -158,44 +162,71 @@ SOFTWARE.
       </xsl:otherwise>
     </xsl:choose>
   </xsl:function>
+  <!-- COMMA WITH SPACE -->
   <xsl:function name="eo:comma">
     <xsl:param name="pos"/>
+    <xsl:param name="tabs"/>
     <xsl:if test="$pos&gt;1">
-      <xsl:text>, </xsl:text>
+      <xsl:text>,</xsl:text>
+      <xsl:value-of select="eo:eol($tabs)"/>
     </xsl:if>
   </xsl:function>
+  <!-- EOL WITH INDENTATION -->
+  <xsl:function name="eo:eol">
+    <xsl:param name="tabs"/>
+    <xsl:value-of select="'&#10;'"/>
+    <xsl:for-each select="1 to $tabs">
+      <xsl:text>  </xsl:text>
+    </xsl:for-each>
+  </xsl:function>
   <!-- Program -->
   <xsl:template match="program">
-    <xsl:text>{</xsl:text>
-    <xsl:variable name="has-package" select="metas/meta/head[text()='package']"/>
-    <xsl:variable name="parts" select="tokenize(metas/meta[head[text()='package']]/tail[1], '\.')"/>
-    <xsl:choose>
-      <xsl:when test="$has-package">
-        <xsl:for-each select="$parts">
-          <xsl:value-of select="."/>
-          <xsl:value-of select="$arrow"/>
-          <xsl:value-of select="$lb"/>
-        </xsl:for-each>
-        <xsl:apply-templates select="objects"/>
-        <xsl:for-each select="$parts">
-          <xsl:value-of select="eo:comma(2)"/>
-          <xsl:value-of select="$lambda"/>
-          <xsl:value-of select="$dashed-arrow"/>
-          <xsl:text>Package</xsl:text>
-          <xsl:value-of select="$rb"/>
-        </xsl:for-each>
-      </xsl:when>
-      <xsl:otherwise>
-        <xsl:apply-templates select="objects"/>
-      </xsl:otherwise>
-    </xsl:choose>
-    <xsl:text>}</xsl:text>
+    <phi>
+      <xsl:text>{</xsl:text>
+      <xsl:variable name="tabs" select="1"/>
+      <xsl:value-of select="eo:eol($tabs)"/>
+      <xsl:variable name="has-package" select="metas/meta/head[text()='package']"/>
+      <xsl:variable name="package" select="metas/meta[head[text()='package']]/tail[1]"/>
+      <xsl:variable name="parts" select="tokenize($package,'\.')"/>
+      <xsl:variable name="length" select="string-length($package)-string-length(replace($package,'\.',''))"/>
+      <xsl:choose>
+        <xsl:when test="$has-package">
+          <xsl:for-each select="$parts">
+            <xsl:value-of select="."/>
+            <xsl:value-of select="$arrow"/>
+            <xsl:value-of select="$lb"/>
+            <xsl:value-of select="eo:eol($tabs+position())"/>
+          </xsl:for-each>
+          <xsl:apply-templates select="objects">
+            <xsl:with-param name="tabs" select="$tabs + $length + 1"/>
+          </xsl:apply-templates>
+          <xsl:for-each select="$parts">
+            <xsl:value-of select="eo:comma(2, $tabs + $length + 2 - position())"/>
+            <xsl:value-of select="$lambda"/>
+            <xsl:value-of select="$dashed-arrow"/>
+            <xsl:text>Package</xsl:text>
+            <xsl:value-of select="eo:eol($tabs + $length + 1 - position())"/>
+            <xsl:value-of select="$rb"/>
+          </xsl:for-each>
+        </xsl:when>
+        <xsl:otherwise>
+          <xsl:apply-templates select="objects">
+            <xsl:with-param name="tabs" select="$tabs"/>
+          </xsl:apply-templates>
+        </xsl:otherwise>
+      </xsl:choose>
+      <xsl:value-of select="eo:eol(0)"/>
+      <xsl:text>}</xsl:text>
+    </phi>
   </xsl:template>
   <!-- Objects  -->
   <xsl:template match="objects">
+    <xsl:param name="tabs"/>
     <xsl:for-each select="o">
-      <xsl:value-of select="eo:comma(position())"/>
-      <xsl:apply-templates select="."/>
+      <xsl:value-of select="eo:comma(position(), $tabs)"/>
+      <xsl:apply-templates select=".">
+        <xsl:with-param name="tabs" select="$tabs"/>
+      </xsl:apply-templates>
     </xsl:for-each>
   </xsl:template>
   <!-- Free attribute -->
@@ -230,6 +261,7 @@ SOFTWARE.
   </xsl:template>
   <!-- Just object -->
   <xsl:template match="o[@base]">
+    <xsl:param name="tabs"/>
     <xsl:if test="@name">
       <xsl:value-of select="eo:specials(@name, true())"/>
       <xsl:value-of select="$arrow"/>
@@ -251,63 +283,85 @@ SOFTWARE.
         </xsl:choose>
         <xsl:if test="count(o)&gt;0">
           <xsl:text>(</xsl:text>
+          <xsl:value-of select="eo:eol($tabs+1)"/>
           <xsl:for-each select="o">
             <xsl:apply-templates select="." mode="application">
               <xsl:with-param name="position" select="position()"/>
+              <xsl:with-param name="tabs" select="$tabs+1"/>
             </xsl:apply-templates>
           </xsl:for-each>
+          <xsl:value-of select="eo:eol($tabs)"/>
           <xsl:text>)</xsl:text>
         </xsl:if>
       </xsl:when>
       <!-- Method -->
       <xsl:otherwise>
-        <xsl:apply-templates select="o[position()=1]"/>
+        <xsl:apply-templates select="o[position()=1]">
+          <xsl:with-param name="tabs" select="$tabs"/>
+        </xsl:apply-templates>
         <xsl:value-of select="eo:specials(@base, true())"/>
         <xsl:if test="count(o)&gt;1">
           <xsl:text>(</xsl:text>
+          <xsl:value-of select="eo:eol($tabs+1)"/>
           <xsl:for-each select="o[position()!=1]">
             <xsl:apply-templates select="." mode="application">
               <xsl:with-param name="position" select="position()"/>
+              <xsl:with-param name="tabs" select="$tabs+1"/>
             </xsl:apply-templates>
           </xsl:for-each>
+          <xsl:value-of select="eo:eol($tabs)"/>
           <xsl:text>)</xsl:text>
         </xsl:if>
       </xsl:otherwise>
     </xsl:choose>
     <!-- Data -->
     <xsl:if test="@data">
+      <xsl:if test="not(@data='bytes')">
+        <xsl:message terminate="yes">
+          <xsl:text>Only 'bytes' is allowed as 'data' attribute to convert to phi-calculus expression. Given: </xsl:text>
+          <xsl:value-of select="@data"/>
+        </xsl:message>
+      </xsl:if>
       <xsl:text>(</xsl:text>
+      <xsl:value-of select="eo:eol($tabs+1)"/>
       <xsl:value-of select="$delta"/>
       <xsl:value-of select="$dashed-arrow"/>
       <xsl:value-of select="eo:bytes(.)"/>
+      <xsl:value-of select="eo:eol($tabs)"/>
       <xsl:text>)</xsl:text>
     </xsl:if>
   </xsl:template>
   <!-- Formation -->
   <xsl:template match="o[not(@base) and (@abstract or @atom)]">
+    <xsl:param name="tabs"/>
     <xsl:if test="@name">
       <xsl:value-of select="eo:specials(@name, true())"/>
       <xsl:value-of select="$arrow"/>
     </xsl:if>
     <xsl:value-of select="$lb"/>
+    <xsl:value-of select="eo:eol($tabs+1)"/>
     <xsl:if test="@atom">
       <xsl:value-of select="$lambda"/>
       <xsl:value-of select="$dashed-arrow"/>
       <xsl:text>Lambda</xsl:text>
       <xsl:if test="count(o)&gt;0">
-        <xsl:text>, </xsl:text>
+        <xsl:value-of select="eo:comma(2, $tabs+1)"/>
       </xsl:if>
     </xsl:if>
     <xsl:for-each select="o">
-      <xsl:value-of select="eo:comma(position())"/>
-      <xsl:apply-templates select="."/>
+      <xsl:value-of select="eo:comma(position(), $tabs+1)"/>
+      <xsl:apply-templates select=".">
+        <xsl:with-param name="tabs" select="$tabs+1"/>
+      </xsl:apply-templates>
     </xsl:for-each>
+    <xsl:value-of select="eo:eol($tabs)"/>
     <xsl:value-of select="$rb"/>
   </xsl:template>
   <!-- Application -->
   <xsl:template match="o" mode="application">
+    <xsl:param name="tabs"/>
     <xsl:param name="position" select="1"/>
-    <xsl:value-of select="eo:comma($position)"/>
+    <xsl:value-of select="eo:comma($position, $tabs)"/>
     <xsl:choose>
       <xsl:when test="@as">
         <xsl:if test="matches(@as,'^[0-9][1-9]*$')">
@@ -321,7 +375,9 @@ SOFTWARE.
       </xsl:otherwise>
     </xsl:choose>
     <xsl:value-of select="$arrow"/>
-    <xsl:apply-templates select="."/>
+    <xsl:apply-templates select=".">
+      <xsl:with-param name="tabs" select="$tabs"/>
+    </xsl:apply-templates>
   </xsl:template>
   <!-- Ignore other elements -->
   <xsl:template match="node()|@*">
diff --git a/eo-maven-plugin/src/test/java/org/eolang/maven/FakeMaven.java b/eo-maven-plugin/src/test/java/org/eolang/maven/FakeMaven.java
index 43d1107fd5..60efd84b65 100644
--- a/eo-maven-plugin/src/test/java/org/eolang/maven/FakeMaven.java
+++ b/eo-maven-plugin/src/test/java/org/eolang/maven/FakeMaven.java
@@ -238,6 +238,7 @@ public <T extends AbstractMojo> FakeMaven execute(final Class<T> mojo) throws IO
             this.params.putIfAbsent("objectionaries", new Objectionaries.Fake());
             this.params.putIfAbsent("rewriteBinaries", true);
             this.params.putIfAbsent("offline", false);
+            this.params.putIfAbsent("phiOptimize", false);
             this.params.putIfAbsent(
                 "eoPortalDir",
                 new File("../eo-runtime/src/main/rust/eo")
diff --git a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/atoms.yaml b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/atoms.yaml
index 40dccf7ccd..17c39f1070 100644
--- a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/atoms.yaml
+++ b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/atoms.yaml
@@ -2,5 +2,14 @@ eo: |
   [] > main /int
   [] > outer
     [] > inner /bytes
-phi:
-  "{main ↦ ⟦λ ⤍ Lambda⟧, outer ↦ ⟦inner ↦ ⟦λ ⤍ Lambda⟧⟧}"
\ No newline at end of file
+phi: |
+  {
+    main ↦ ⟦
+      λ ⤍ Lambda
+    ⟧,
+    outer ↦ ⟦
+      inner ↦ ⟦
+        λ ⤍ Lambda
+      ⟧
+    ⟧
+  }
\ No newline at end of file
diff --git a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/bindings.yaml b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/bindings.yaml
index 07a27790c0..53fee55501 100644
--- a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/bindings.yaml
+++ b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/bindings.yaml
@@ -4,5 +4,18 @@ eo: |
     [z]:abs
       w > @
     5:five
-phi:
-  "{xyz ↦ Φ.org.eolang.x(attr ↦ Φ.org.eolang.y, abs ↦ ⟦z ↦ ∅, φ ↦ Φ.org.eolang.w⟧, five ↦ Φ.org.eolang.int(α0 ↦ Φ.org.eolang.bytes(Δ ⤍ 00-00-00-00-00-00-00-05)))}"
\ No newline at end of file
+phi: |
+  {
+    xyz ↦ Φ.org.eolang.x(
+      attr ↦ Φ.org.eolang.y,
+      abs ↦ ⟦
+        z ↦ ∅,
+        φ ↦ Φ.org.eolang.w
+      ⟧,
+      five ↦ Φ.org.eolang.int(
+        α0 ↦ Φ.org.eolang.bytes(
+          Δ ⤍ 00-00-00-00-00-00-00-05
+        )
+      )
+    )
+  }
\ No newline at end of file
diff --git a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/custom-alias.yaml b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/custom-alias.yaml
index 2f542bf5ca..bb40ecb9a1 100644
--- a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/custom-alias.yaml
+++ b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/custom-alias.yaml
@@ -4,4 +4,18 @@ eo: |
   
   [y] > main
     x y > z
-phi: "{foo ↦ ⟦bar ↦ ⟦main ↦ ⟦y ↦ ∅, z ↦ Φ.com.yegor256.x(α0 ↦ ξ.y)⟧, λ ⤍ Package⟧, λ ⤍ Package⟧}"
\ No newline at end of file
+phi: |
+  {
+    foo ↦ ⟦
+      bar ↦ ⟦
+        main ↦ ⟦
+          y ↦ ∅,
+          z ↦ Φ.com.yegor256.x(
+            α0 ↦ ξ.y
+          )
+        ⟧,
+        λ ⤍ Package
+      ⟧,
+      λ ⤍ Package
+    ⟧
+  }
\ No newline at end of file
diff --git a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/empty-bytes.yaml b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/empty-bytes.yaml
index 34a3b65221..de280c32d5 100644
--- a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/empty-bytes.yaml
+++ b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/empty-bytes.yaml
@@ -1,2 +1,7 @@
 eo: -- > empty
-phi: "{empty ↦ Φ.org.eolang.bytes(Δ ⤍ --)}"
\ No newline at end of file
+phi: |
+  {
+    empty ↦ Φ.org.eolang.bytes(
+      Δ ⤍ --
+    )
+  }
\ No newline at end of file
diff --git a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/fibonaci.yaml b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/fibonaci.yaml
index d6be21b86e..87f4cca69a 100644
--- a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/fibonaci.yaml
+++ b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/fibonaci.yaml
@@ -12,4 +12,43 @@ eo: |
           n.minus 1
         fibonacci
           n.minus 2
-phi: "{eo ↦ ⟦example ↦ ⟦fibonacci ↦ ⟦n ↦ ∅, φ ↦ ξ.n.lt(α0 ↦ Φ.org.eolang.int(α0 ↦ Φ.org.eolang.bytes(Δ ⤍ 00-00-00-00-00-00-00-02))).if(α0 ↦ ξ.n, α1 ↦ ξ.ρ.fibonacci(α0 ↦ ξ.n.minus(α0 ↦ Φ.org.eolang.int(α0 ↦ Φ.org.eolang.bytes(Δ ⤍ 00-00-00-00-00-00-00-01)))).plus(α0 ↦ ξ.ρ.fibonacci(α0 ↦ ξ.n.minus(α0 ↦ Φ.org.eolang.int(α0 ↦ Φ.org.eolang.bytes(Δ ⤍ 00-00-00-00-00-00-00-02))))))⟧, λ ⤍ Package⟧, λ ⤍ Package⟧}"
\ No newline at end of file
+phi: |
+  {
+    eo ↦ ⟦
+      example ↦ ⟦
+        fibonacci ↦ ⟦
+          n ↦ ∅,
+          φ ↦ ξ.n.lt(
+            α0 ↦ Φ.org.eolang.int(
+              α0 ↦ Φ.org.eolang.bytes(
+                Δ ⤍ 00-00-00-00-00-00-00-02
+              )
+            )
+          ).if(
+            α0 ↦ ξ.n,
+            α1 ↦ ξ.ρ.fibonacci(
+              α0 ↦ ξ.n.minus(
+                α0 ↦ Φ.org.eolang.int(
+                  α0 ↦ Φ.org.eolang.bytes(
+                    Δ ⤍ 00-00-00-00-00-00-00-01
+                  )
+                )
+              )
+            ).plus(
+              α0 ↦ ξ.ρ.fibonacci(
+                α0 ↦ ξ.n.minus(
+                  α0 ↦ Φ.org.eolang.int(
+                    α0 ↦ Φ.org.eolang.bytes(
+                      Δ ⤍ 00-00-00-00-00-00-00-02
+                    )
+                  )
+                )
+              )
+            )
+          )
+        ⟧,
+        λ ⤍ Package
+      ⟧,
+      λ ⤍ Package
+    ⟧
+  }
\ No newline at end of file
diff --git a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/full-path.yaml b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/full-path.yaml
index 5b64bd8ce3..c03eb98c22 100644
--- a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/full-path.yaml
+++ b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/full-path.yaml
@@ -1,5 +1,8 @@
 eo: |
   QQ.io.stdout > std
   Q.org.eolang.x > y
-phi:
-  "{std ↦ Φ.org.eolang.io.stdout, y ↦ Φ.org.eolang.x}"
\ No newline at end of file
+phi: |
+  {
+    std ↦ Φ.org.eolang.io.stdout,
+    y ↦ Φ.org.eolang.x
+  }
\ No newline at end of file
diff --git a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/jeo-part.yaml b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/jeo-part.yaml
new file mode 100644
index 0000000000..8774785dde
--- /dev/null
+++ b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/jeo-part.yaml
@@ -0,0 +1,40 @@
+eo: |
+  +package org.eolang.benchmark
+
+  [] > j$A
+    32 > access
+    "java/lang/Object" > supername
+    * > interfaces
+      "org/eolang/benchmark/F"
+phi: |
+  {
+    org ↦ ⟦
+      eolang ↦ ⟦
+        benchmark ↦ ⟦
+          j$A ↦ ⟦
+            access ↦ Φ.org.eolang.int(
+              α0 ↦ Φ.org.eolang.bytes(
+                Δ ⤍ 00-00-00-00-00-00-00-20
+              )
+            ),
+            supername ↦ Φ.org.eolang.string(
+              α0 ↦ Φ.org.eolang.bytes(
+                Δ ⤍ 6A-61-76-61-2F-6C-61-6E-67-2F-4F-62-6A-65-63-74
+              )
+            ),
+            interfaces ↦ Φ.org.eolang.tuple(
+              α0 ↦ Φ.org.eolang.tuple.empty,
+              α1 ↦ Φ.org.eolang.string(
+                α0 ↦ Φ.org.eolang.bytes(
+                  Δ ⤍ 6F-72-67-2F-65-6F-6C-61-6E-67-2F-62-65-6E-63-68-6D-61-72-6B-2F-46
+                )
+              )
+            )
+          ⟧,
+          λ ⤍ Package
+        ⟧,
+        λ ⤍ Package
+      ⟧,
+      λ ⤍ Package
+    ⟧
+  }
\ No newline at end of file
diff --git a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/method.yaml b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/method.yaml
index 309b7b901a..5316ab69d9 100644
--- a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/method.yaml
+++ b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/method.yaml
@@ -1,2 +1,5 @@
 eo: x.y.z > xyz
-phi: "{xyz ↦ Φ.org.eolang.x.y.z}"
\ No newline at end of file
+phi: |
+  {
+    xyz ↦ Φ.org.eolang.x.y.z
+  }
\ No newline at end of file
diff --git a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/nested.yaml b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/nested.yaml
index a266f9720b..71f6503f13 100644
--- a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/nested.yaml
+++ b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/nested.yaml
@@ -7,4 +7,25 @@ eo: |
           main 5 > five
           a > b
           d > e
-phi: "{main ↦ ⟦a ↦ ∅, x ↦ ⟦y ↦ ⟦d ↦ ξ.ρ.ρ.a, z ↦ ⟦five ↦ ξ.ρ.ρ.ρ.ρ.main(α0 ↦ Φ.org.eolang.int(α0 ↦ Φ.org.eolang.bytes(Δ ⤍ 00-00-00-00-00-00-00-05))), b ↦ ξ.ρ.ρ.ρ.a, e ↦ ξ.ρ.d⟧⟧⟧⟧}"
\ No newline at end of file
+phi: |
+  {
+    main ↦ ⟦
+      a ↦ ∅,
+      x ↦ ⟦
+        y ↦ ⟦
+          d ↦ ξ.ρ.ρ.a,
+          z ↦ ⟦
+            five ↦ ξ.ρ.ρ.ρ.ρ.main(
+              α0 ↦ Φ.org.eolang.int(
+                α0 ↦ Φ.org.eolang.bytes(
+                  Δ ⤍ 00-00-00-00-00-00-00-05
+                )
+              )
+            ),
+            b ↦ ξ.ρ.ρ.ρ.a,
+            e ↦ ξ.ρ.d
+          ⟧
+        ⟧
+      ⟧
+    ⟧
+  }
\ No newline at end of file
diff --git a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/one-byte.yaml b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/one-byte.yaml
index 284f3dcfd2..a6e82afea9 100644
--- a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/one-byte.yaml
+++ b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/one-byte.yaml
@@ -1,2 +1,7 @@
 eo: A2- > bts
-phi: "{bts ↦ Φ.org.eolang.bytes(Δ ⤍ A2-)}"
\ No newline at end of file
+phi: |
+  {
+    bts ↦ Φ.org.eolang.bytes(
+      Δ ⤍ A2-
+    )
+  }
\ No newline at end of file
diff --git a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/package.yaml b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/package.yaml
index 26d86454b1..0f5d6c3964 100644
--- a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/package.yaml
+++ b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/package.yaml
@@ -3,4 +3,18 @@ eo: |
   
   [] > main
     stdout > @
-phi: "{foo ↦ ⟦bar ↦ ⟦baz ↦ ⟦main ↦ ⟦φ ↦ Φ.org.eolang.stdout⟧, λ ⤍ Package⟧, λ ⤍ Package⟧, λ ⤍ Package⟧}"
\ No newline at end of file
+phi: |
+  {
+    foo ↦ ⟦
+      bar ↦ ⟦
+        baz ↦ ⟦
+          main ↦ ⟦
+            φ ↦ Φ.org.eolang.stdout
+          ⟧,
+          λ ⤍ Package
+        ⟧,
+        λ ⤍ Package
+      ⟧,
+      λ ⤍ Package
+    ⟧
+  }
\ No newline at end of file
diff --git a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/specials.yaml b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/specials.yaml
index 2cc1018000..abccecb6fe 100644
--- a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/specials.yaml
+++ b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/specials.yaml
@@ -6,4 +6,14 @@ eo: |
     < > vtx
     ^.< > self
     @.@ > phi
-phi: "{main ↦ ⟦x ↦ ξ.ρ.x, h ↦ Φ.org.eolang.y.σ, a ↦ ξ.a, vtx ↦ ξ.ν, self ↦ ξ.ρ.ν, phi ↦ ξ.φ.φ⟧}"
\ No newline at end of file
+phi: |
+  {
+    main ↦ ⟦
+      x ↦ ξ.ρ.x,
+      h ↦ Φ.org.eolang.y.σ,
+      a ↦ ξ.a,
+      vtx ↦ ξ.ν,
+      self ↦ ξ.ρ.ν,
+      phi ↦ ξ.φ.φ
+    ⟧
+  }
\ No newline at end of file
diff --git a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/with-data.yaml b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/with-data.yaml
index f5333e55a8..8713c553b6 100644
--- a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/with-data.yaml
+++ b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/with-data.yaml
@@ -1,2 +1,9 @@
 eo: 5 > five
-phi: "{five ↦ Φ.org.eolang.int(α0 ↦ Φ.org.eolang.bytes(Δ ⤍ 00-00-00-00-00-00-00-05))}"
+phi: |
+  {
+    five ↦ Φ.org.eolang.int(
+      α0 ↦ Φ.org.eolang.bytes(
+        Δ ⤍ 00-00-00-00-00-00-00-05
+      )
+    )
+  }
\ No newline at end of file
diff --git a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/with-free-attributes.yaml b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/with-free-attributes.yaml
index de5353fb8c..633ad837fd 100644
--- a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/with-free-attributes.yaml
+++ b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/with-free-attributes.yaml
@@ -1,5 +1,11 @@
 eo: |
   [a b] > c
     d > @
-phi:
-  "{c ↦ ⟦a ↦ ∅, b ↦ ∅, φ ↦ Φ.org.eolang.d⟧}"
\ No newline at end of file
+phi: |
+  {
+    c ↦ ⟦
+      a ↦ ∅,
+      b ↦ ∅,
+      φ ↦ Φ.org.eolang.d
+    ⟧
+  }
\ No newline at end of file
diff --git a/eo-parser/src/main/java/org/eolang/parser/ParsingTrain.java b/eo-parser/src/main/java/org/eolang/parser/ParsingTrain.java
index d73f65bec4..c1cefd23bb 100644
--- a/eo-parser/src/main/java/org/eolang/parser/ParsingTrain.java
+++ b/eo-parser/src/main/java/org/eolang/parser/ParsingTrain.java
@@ -121,36 +121,39 @@ public ParsingTrain() {
      */
     ParsingTrain(final String... sheets) {
         super(
-            new TrJoined<>(
-                new TrDefault<>(
-                    new StEndless(
-                        new StLambda(ParsingTrain.TUPLES::transform)
-                    )
-                ),
-                new TrLambda(
-                    new TrFast(
-                        new TrLambda(
-                            new TrLogged(
-                                new TrClasspath<>(sheets).back(),
-                                ParsingTrain.class,
-                                Level.FINEST
+            new TrLambda(
+                new TrFast(
+                    new TrLambda(
+                        new TrLogged(
+                            new TrJoined<>(
+                                new TrDefault<>(
+                                    new StEndless(
+                                        new StLambda(
+                                            "stars-to-tuples",
+                                            ParsingTrain.TUPLES::transform
+                                        )
+                                    )
+                                ),
+                                new TrClasspath<>(sheets).back()
                             ),
-                            StEoLogged::new
+                            ParsingTrain.class,
+                            Level.FINEST
                         ),
-                        TrFast.class,
-                        500L
+                        StEoLogged::new
                     ),
-                    shift -> new StSequence(
-                        shift.uid(),
-                        xml -> xml.nodes("//error[@severity='critical']").isEmpty(),
-                        new StAfter(
-                            shift,
-                            new StLambda(
-                                shift::uid,
-                                (pos, xml) -> ParsingTrain.EACH.with("step", pos)
-                                    .with("sheet", shift.uid())
-                                    .transform(xml)
-                            )
+                    TrFast.class,
+                    500L
+                ),
+                shift -> new StSequence(
+                    shift.uid(),
+                    xml -> xml.nodes("//error[@severity='critical']").isEmpty(),
+                    new StAfter(
+                        shift,
+                        new StLambda(
+                            shift::uid,
+                            (pos, xml) -> ParsingTrain.EACH.with("step", pos)
+                                .with("sheet", shift.uid())
+                                .transform(xml)
                         )
                     )
                 )
diff --git a/eo-parser/src/main/java/org/eolang/parser/XePhiListener.java b/eo-parser/src/main/java/org/eolang/parser/XePhiListener.java
index 0b25cd0b4d..2162b5a868 100644
--- a/eo-parser/src/main/java/org/eolang/parser/XePhiListener.java
+++ b/eo-parser/src/main/java/org/eolang/parser/XePhiListener.java
@@ -298,7 +298,7 @@ public void exitDeltaBidning(final PhiParser.DeltaBidningContext ctx) {
     @Override
     public void enterLambdaBidning(final PhiParser.LambdaBidningContext ctx) {
         if (!ctx.FUNCTION().getText().equals(XePhiListener.LAMBDA_PACKAGE)) {
-            this.objects().prop("atom");
+            this.objects().prop("atom", "?");
         }
     }
 
diff --git a/eo-parser/src/main/resources/XMIR.xsd b/eo-parser/src/main/resources/XMIR.xsd
index 7f9e34ffdf..ec517a7b73 100644
--- a/eo-parser/src/main/resources/XMIR.xsd
+++ b/eo-parser/src/main/resources/XMIR.xsd
@@ -68,6 +68,7 @@ SOFTWARE.
               <xs:complexType>
                 <xs:simpleContent>
                   <xs:extension base="xs:string">
+                    <xs:attribute name="check"/>
                     <xs:attribute name="line" use="required"/>
                     <xs:attribute name="severity" use="required">
                       <xs:simpleType>
@@ -78,6 +79,8 @@ SOFTWARE.
                         </xs:restriction>
                       </xs:simpleType>
                     </xs:attribute>
+                    <xs:attribute name="sheet"/>
+                    <xs:attribute name="step"/>
                   </xs:extension>
                 </xs:simpleContent>
               </xs:complexType>
@@ -103,7 +106,8 @@ SOFTWARE.
                   <xs:element name="tail" type="xs:string"/>
                   <xs:element name="part" type="xs:string" minOccurs="0" maxOccurs="unbounded"/>
                 </xs:sequence>
-                <xs:attribute name="line" type="xs:decimal"/>
+                <xs:attribute name="line"/>
+                <xs:attribute name="expanded"/>
               </xs:complexType>
             </xs:element>
           </xs:sequence>
diff --git a/eo-parser/src/main/resources/org/eolang/parser/errors/external-weak-typed-atoms.xsl b/eo-parser/src/main/resources/org/eolang/parser/errors/external-weak-typed-atoms.xsl
index b69bc1de59..41fb0480e6 100644
--- a/eo-parser/src/main/resources/org/eolang/parser/errors/external-weak-typed-atoms.xsl
+++ b/eo-parser/src/main/resources/org/eolang/parser/errors/external-weak-typed-atoms.xsl
@@ -40,9 +40,6 @@ SOFTWARE.
             <xsl:attribute name="severity">
               <xsl:text>error</xsl:text>
             </xsl:attribute>
-            <xsl:attribute name="msg">
-              <xsl:value-of select="$package"/>
-            </xsl:attribute>
             <xsl:text>Weak typing /? is allowed only inside org.eolang package</xsl:text>
           </xsl:element>
         </xsl:for-each>
diff --git a/eo-parser/src/test/java/org/eolang/parser/ParsingTrainTest.java b/eo-parser/src/test/java/org/eolang/parser/ParsingTrainTest.java
index cf73d50e28..6824380743 100644
--- a/eo-parser/src/test/java/org/eolang/parser/ParsingTrainTest.java
+++ b/eo-parser/src/test/java/org/eolang/parser/ParsingTrainTest.java
@@ -73,7 +73,7 @@ void stopsPipeline() {
                 new ParsingTrain()
             ).pass(xml),
             XhtmlMatchers.hasXPaths(
-                "/program/sheets[count(sheet)=2]",
+                "/program/sheets[count(sheet)=3]",
                 "/program/errors/error[@severity='critical']"
             )
         );