Cookies

There is no cookie banner because there is nothing to consent to. The site sets no cookie until you sign in, and then only the ones below, each strictly necessary for the thing you asked for.

Cookie	Set when	Purpose	Lifetime
`__Secure-authjs.session-token`	You sign in	Identifies your session on the server, which is a database row. HttpOnly, Secure, SameSite=Lax; holds a random token and nothing else.	30 days, or until you sign out
`__Host-authjs.csrf-token`, `__Secure-authjs.callback-url`, `__Secure-authjs.state`, `__Secure-authjs.pkce.code_verifier`, `__Secure-authjs.nonce`	During sign-in only	The state, nonce and PKCE verifier of the sign-in in progress, and where to return to, so the answer from the provider can be checked against the question.	15 minutes
`gh_state`	You press Install the App on a repository on Connectors	A random value the return from GitHub has to carry back, so an installation somebody else started cannot be attached to your account. Scoped to `/api/github`; HttpOnly, SameSite=Lax.	15 minutes

Under the Dutch Telecommunicatiewet and the ePrivacy rules behind it, cookies that are strictly necessary to provide a service the visitor asked for need no consent. All of these are. There are no analytics cookies, no advertising cookies and no embedded players; anything external on the site is a plain link, with one exception: pressing Pick a zip on Drive on Connectors loads Google's file picker from apis.google.com, which runs in Google's own frame with whatever cookies Google sets for a signed-in Google account, exactly as Drive itself would. It is loaded only then, and on no other page.

Browser storage that is not a cookie

Two parts of the site keep data in your browser, on your own machine, and never send it anywhere:

The editor at /editor/ keeps the packs you make and edit in IndexedDB, and a few settings in localStorage, so your work is there on the next visit. If you point it at your copy of Minecraft, the textures it extracts are kept the same way. The editor's start page has a reset that clears all of it.
Your shelf - the packs and pieces you save and the outfits you keep without an account - is a list of names in localStorage: which pack, which piece, which pieces an outfit wears. No pictures and no files, and it is never sent anywhere. It is what your library and the wardrobe show you when you are not signed in, and signing in offers to keep the same things in an account instead.

Clearing site data in your browser removes all of it, including a shelf that has never been signed in - so export it to a file first if it matters to you.