Two Claude skills at work cover the two ways a Shopify client repo starts life, and having written both I'm fairly sure the numbered steps are the part nobody needed written down. The four or five places where the instruction is to stop are what earn the disk space.
Our template for new Shopify projects contains no theme code at all, and the most useful thing in it turned out to be the part that says which files we own, which ones belong to the client, and which ones should never have been copied in.
How a Shopify theme change at work went from somebody typing a push command on a laptop to one repo of shared GitHub Actions workflows, and the backup cleanup I had to get wrong three times before I stopped overthinking it.
Next week Shopify stops rendering checkout.liquid on 3 of the checkout steps, and going through one store's customizations turned up 8 pieces of decoration and 1 thing that was the entire business.
A row of six related products came out one card short on about a third of a client's catalog, and the thing eating the missing card was a limit I'd never read about, being spent by a block I hadn't written.