Theme Installer
The theme installer is a new feature added in Tiki 19 that allowed adding of a theme packaged in a zip file through the use of the Console. This is related to Packages. You can also from Tiki 20 install themes that are packaged within Packages that extend Tiki.
The available commands are:
php console.php theme:install <file>
php console.php theme:update <file>
php console.php theme:remove <theme>