Privacy

This site is static documentation with demos that run in your browser. It has no accounts, no comments and no forms. This page explains which cookies and similar technologies it uses, why, and how you control them.

Last updated: November 2026.

Cookies and browser storage

Cookies are small pieces of data a site keeps on your device. This site also uses your browser’s local and session storage for the same purposes, and treats them under the same rules.

Analytics

The site counts visits with Google Analytics 4, loaded through Google Tag Manager in Google’s Consent Mode v2. Until you accept analytics, it runs without cookies: Google receives a visit without an identifier that ties it to your earlier or later visits.

• In the European Union a banner asks first. Nothing beyond the cookieless count happens until you choose.
• Elsewhere analytics is allowed by default. You can turn it off any time with the button below.

To decide whether to show the banner, the page asks this site’s own server (/api-shared/ip) whether your address is in the EU. Only the yes or no comes back to the page; the address is not stored. If the server cannot tell, the banner is shown.

Categories

Category	What it covers
Essential	Your cookie choice itself. Always on.
Analytics	Google Analytics cookies, which tell visits apart. Off until you accept in the EU.
Marketing	Advertising. The site uses none; the category records your choice in case that ever changes.

What is stored

Name	Where	Purpose	Duration	Category
gkg-consent	local storage	Your cookie choice	Until you clear it	Essential
gkg-eu-check	session storage	Whether the banner applies in your region, so the check runs once	Until the tab closes	Essential
_ga, _ga_…	cookies	Google Analytics: tells visits apart	Up to 2 years	Analytics, only once allowed
starlight-theme	local storage	Light or Dark, once you pick it in the header (Auto removes it)	Until you clear it	Set at your request
sl-sidebar-state	session storage	Which sidebar groups are open, and how far it is scrolled	Until the tab closes	Set at your request

Some other things stay in your browser and never leave it:

• A theme in a link (#theme=…, which Play writes as you edit) stays in the address: the part after # is never sent to the site.
• The orbit demo’s data, once you ask for it, is kept in your browser’s Cache Storage for two hours, so the demo does not download it again; so is a refusal from CelesTrak.

Change your choice

Cookie settings

The same button is in the footer of every page. You can also clear cookies and site data in your browser’s settings, and block Google Analytics with the Google Analytics opt-out add-on.

The embed script and the demos

Pages under /embed/ and the demos under /demo/, which other sites load to show a grid, carry no analytics and no banner. live-grid.js stores nothing in your browser and fetches only the example it shows (its module and fonts) from this site.

The demos run on simulated data unless you start a live one. A live demo connects your browser directly to the public source it names on the page, and that source sees your IP address:

• the Finnish marine traffic data of Fintraffic (digitraffic.fi);
• Wikimedia’s public stream of recent changes (stream.wikimedia.org);
• CelesTrak (celestrak.org, in the United States), for the orbit demo’s orbital elements, only when you press its download button.

The Munich demo uses the MVV’s published timetable, served from this site, and connects to no one.

Hosting

The site runs on a server at Hetzner in Germany, behind Cloudflare. Both process your IP address and the request to deliver the pages and protect the service, as any web host does.

Questions

Open an issue in the repository.