Hi Kupili,
It is indeed hardcoded, but with a filter.
So, add a filter and hook into tc_time_archive_header_content to achieve your purpose.
Something like this bit of code can be added to your child theme’s functions.php to overwrite the existing header.
add_filter('tc_time_archive_header_content','my_time_archive_header_content');
function my_time_archive_header_content($content) {
if ( is_day() || is_month() || is_year() ) {
$archive_type = is_day() ? sprintf( __( 'My Daily Archives: %s' , 'customizr' ), '<span>' . get_the_date() . '</span>' ) : __( 'Archives' , 'customizr' );
$archive_type = is_month() ? sprintf( __( 'My Monthly Archives: %s' , 'customizr' ), '<span>' . get_the_date( _x( 'F Y' , 'monthly archives date format' , 'customizr' ) ) . '</span>' ) : $archive_type;
$archive_type = is_year() ? sprintf( __( 'My Yearly Archives: %s' , 'customizr' ), '<span>' . get_the_date( _x( 'Y' , 'yearly archives date format' , 'customizr' ) ) . '</span>' ) : $archive_type;
$content = sprintf('<h1 class="%1$s">%2$s</h1>',
apply_filters( 'tc_archive_icon', 'format-icon' ),
$archive_type
);
}
return $content;
}