I have now enabled gzip compression on this website. This means all text resources are now served compressed, which results in quicker page (down)loads.
I only recently noticed files are served uncompressed, and so I went looking to see whether one has control over this part of GitLab Pages to change this. And yes, you do! They have a handy section on their documentation pages that tells you how to enable compression, complete with code snipped for your/their CI.
I’m only using gzip at this point, though. While I wanted to try using the newer – and supposedly better – Brotli format, the VM I’m using to build this site doesn’t have it installed. And I couldn’t be bothered to do that.