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diff --git a/www/wiki/includes/collation/CollationEt.php b/www/wiki/includes/collation/CollationEt.php
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+<?php
+/**
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+/**
+ * Workaround for incorrect collation of Estonian language ('et') in ICU (T56168).
+ *
+ * 'W' and 'V' should not be considered the same letter for the purposes of collation in modern
+ * Estonian. We work around this by replacing 'W' and 'w' with 'ᴡ' U+1D21 'LATIN LETTER SMALL
+ * CAPITAL W' for sortkey generation, which is collated like 'W' and is not tailored to have the
+ * same primary weight as 'V' in Estonian.
+ *
+ * @since 1.24
+ */
+class CollationEt extends IcuCollation {
+	public function __construct() {
+		parent::__construct( 'et' );
+	}
+
+	private static function mangle( $string ) {
+		return str_replace(
+			[ 'w', 'W' ],
+			'ᴡ', // U+1D21 'LATIN LETTER SMALL CAPITAL W'
+			$string
+		);
+	}
+
+	private static function unmangle( $string ) {
+		// Casing data is lost…
+		return str_replace(
+			'ᴡ', // U+1D21 'LATIN LETTER SMALL CAPITAL W'
+			'W',
+			$string
+		);
+	}
+
+	public function getSortKey( $string ) {
+		return parent::getSortKey( self::mangle( $string ) );
+	}
+
+	public function getFirstLetter( $string ) {
+		return self::unmangle( parent::getFirstLetter( self::mangle( $string ) ) );
+	}
+}