Manual:GenerateJsonI18n.php

generateJsonI18n.php is used to generate json formatted i18n from the legacy PHP array based mediawiki i18n file.

Usage
Usage: php generateJSONi18n.php phpfile targetfolder

Arguments
 * --langcode: Language code; only needed for converting core i18n files

Suggested migration process
If your extension has not been converted already.
 * Make sure you have the latest code
 * Create the i18n directory
 * Run the script
 * Replace the i18n file with BC code
 * Update the extension entry file to add $wgMessageDirs['YourExtension'] = __DIR__ . '/i18n';
 * Commit it to gerrit if the extension is hosted there
 * Add Siebrand and Raimond as reviewers if the extension is translated in translatewiki.net
 * Wait for review and all should go smoothly