Is your feature request related to a problem? Please describe.
Just noticed that Gutenberg adds a CSS file (gutenberg/build/core-blocks/style.css) to the front end, breaking my site's optimisation.
Describe the solution you'd like
Please provide an option to not add that file to "head". Thanks.
Tested and confirmed that gutenberg/build/core-blocks/style.css is loaded on the front-end with Gutenberg:

Seen at http://alittletestblog.com/2018/07/25/summer-night-riverside/ running WordPress 4.9.7 and Gutenberg 3.3.0 using Firefox 61.0.1 on macOS 10.13.6.
I think the solution for this will be to add theme support to replace such styles. I am not sure how to do that, and hopefully someone will chime in with a more technical answer!
You should be able to use something like this (haven't tested, admittedly, but this should help get you started at least):
add_action( 'wp_enqueue_scripts', function () {
wp_dequeue_style( 'wp-core-blocks' );
} );
@chrisvanpatten thanks for the quick response. I added only
wp_dequeue_style( 'wp-core-blocks' );
to my theme styles function and it works.
Cheers!
Most helpful comment
You should be able to use something like this (haven't tested, admittedly, but this should help get you started at least):