I don’t think there’s any official documentation about that, but you can have a look at the sanitize_user
function in wp-includes/formatting.php:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | function sanitize_user( $username, $strict = false ) { $raw_username = $username; $username = wp_strip_all_tags( $username ); $username = remove_accents( $username ); // Kill octets $username = preg_replace( '|%([a-fA-F0-9][a-fA-F0-9])|', '', $username ); $username = preg_replace( '/&.+?;/', '', $username ); // Kill entities // If strict, reduce to ASCII for max portability. if ( $strict ) $username = trim( $username ); // Consolidate contiguous whitespace $username = preg_replace( '|\s+|', ' ', $username ); return apply_filters( 'sanitize_user', $username, $raw_username, $strict ); } |
You could hook into that function and override the default behavior with your own.
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