Entry summary prototype

lib/Parser/XML/Entry.php

@@ -110,7 +110,9 @@ class Entry extends Construct implements \MensBeam\Lax\Parser\Entry {
     }
 
     public function getSummary(): ?Text {
-        return null;
+        return $this->fetchAtomText("atom:summary")                     // Atom summary
+            ?? $this->fetchText("gplay:description", self::TEXT_PLAIN)  // Google Play podcast description
+            ?? $this->fetchText("apple:summary", self::TEXT_PLAIN);     // iTunes podcast summary
     }
 
     public function getBanner(): ?Url {