wp-includes/pomo/po.php:319Helper function for read_entry
$contextstringbool protected static function is_final( $context ) { return ( 'msgstr' === $context ) || ( 'msgstr_plural' === $context ); }Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/pomo/po.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.