What do I do with the "Allow this website to use space on your disk" message?

The Safari web browser may show you this message when loading the med.firecracker.me/app website: "Allow this website to use space on your disk." Allowing this permission makes our app faster and enables offline support. Just click "Allow" and the site should work as intended in Safari. Otherwise, recommended web browsers for our beta website include modern versions of Chrome and Firefox. We would recommend that you disable browser extensions for our website.