SEO

You have successfully set your canonical URL. This will prevent duplicate content on your website.

You don't have a canonical URL set on your site, which might result in duplicate content, which can result in negative results in Google.

In some situations one single page might be accessible in 2 or even 3 ways. For example, if you have a folder in your resource-tree called 'Services' with ID 34, the URL can be either one of these three: https://site.ext/services or https://site.ext/services/ or https://site.ext/index.php?id=34. To prevent this, set a canonical URL.

<link rel="canonical" href="[[~[[*id]]? &scheme=`full`]]">

If you care about Search Engine Optimisation, you should continue reading. There are some very useful and respected Extras (the MODX name for a 'plugin') which help increase your SEO performance. Here's a small selection of the MODX Extras section: SEO Pro is your personal onpage SEO assistant, SEO Tab will help you with (automatic) 301 redirects to prevent 404 pages and SEO Suite will automatically detect 404 pages and fix them.

Security

You have hidden your core-folder from the public successfully. This will make your website a lot more secure for unwanted visitors.

You have a potential security issue on your website, because your MODX core-folder is exposed to the public which makes it easier to be hacked. If an exploit is released for MODX and your core folder is exposed to the public, you're taking a huge risk.

Hiding your core-folder from the public by moving it up one level from your document root will greatly increase the security of your website, even if you're not up-to-date.

Performance

You have successfully minified your JavaScript, which will increase the loading speed of your website. Good job!

There are multiple CSS / JavaScript includes on your website, which will decrease the rate at which your site is being loaded. Google recommends to have your primary content loaded and rendered as soon as possible. This will prevent that.

To increase performance, minify all files into 1 file for each type. One minified CSS file and 1 or 2 JS-files. You can minify them by using Gulp/Grunt, or by doing it dynamically using the ModxMinify extra, which can be found here.

Example:
<link rel="stylesheet" href="[[modxMinify? &group=`css`]]" />