I really love mailcow. What I hate is the loading of the many external resources, like stylesheets, scripts and webfonts. So I wrote a bash script to convert an installed mailcow-dockerized to a true local setup.
It scans the header.inc.php to acquire the right version numbers and then downloads the external js-libraries and stylesheets. Then it scans those files for other external resources - such as webfonts - and downloads them, too. (For this step it requires google-font-download script by Clemens Lang, https://github.com/neverpanic/google-font-download).
After that it patches all required files to use the local resources instead of the external ones.