Please note that since the advent of HTTP/2 and parallel asset downloads, optimizations such as CSS and JS concatenation are no longer necessary, and not concatenating your assets will often provide better performance. Minification is still always recommended (and UberMenu ships with a minified JS file by default).
CSS
UberMenu loads two CSS stylesheets by default: the core ubermenu.min.css file and a skin file of your choosing.
JS
UberMenu loads one javascript file by default. The script is minified and compiled. (You can view the non-minified version with SCRIPT_DEBUG enabled)
Icons
UberMenu loads Font Awesome by default, which provides icons that can be assigned to menu items. If you don’t intend to assign icons to your items, then you can disable Font Awesome and use the Essential Icon SVGs instead.
Optimization
As with any site, once you move to production, it’s recommended that you optimize your assets even further. Using a plugin like Autoptimize will concatenate and minify all of your javascript and CSS, reducing your HTTP requests and bandwidth required to load your site – so the site will load faster.
Please note that not all plugins’ assets can be properly optimized. If you have another plugin that causes problems, it can break UberMenu when all the CSS and JS is combined. In this case, you’ll just need to disable the optimization plugin, or configure it to avoid errors.
Note that you should not enable caching or optimization plugins during development, as they can prevent you from seeing changes to your site