This change (automatically compiling templates in site customizations) is now complete!
https://github.com/discourse/discourse/commit/43d63367fdf39dc5f69b640936ac19cd817f6631
This means we no longer ship 66K gzipped Ember template compiler AND we stop shipping 11K gzipped handlebars (and instead ship 3.7K gzipped runtime)
Total savings on initial load is approx 73K also this is a bunch of code that is no longer evaluated and kept in memory which is another huge saving.