You can also give the tools directly to the customers, and you can bundle/package the tools into future versions of the product. A common pattern is to have a public git repo and the customers can git pull to get the latest versions of the support tools.
Shipping tools as a git repository sounds delightful, at least to my engineering-minded heart. So painless! Free versioning! Rollbacks!
If we were in the devtools business I would certainly consider that. Sadly, though, owners of small retail businesses tend not to be as comfortable with version control as one might hope…