Privacy and Site Policies
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Privacy
Section titled “Privacy”The webmaster of BlackHole.org is Jie Ren.
Hosting and analytics. Cloudflare Pages hosts and delivers the website, and Cloudflare Web Analytics measures page use and loading performance worldwide. According to Cloudflare, its analytics uses no cookies or browser storage and does not fingerprint visitors. These analytics limits do not describe Cloudflare’s separate hosting and security processing. See Cloudflare’s analytics privacy description and privacy policy for its data handling, retention, and international processing.
Browser preferences. The site stores theme and formula-image-size choices locally, and sidebar state for the browser session. These preferences stay in your browser; clear this site’s browser data to remove them. The site does not change its behavior in response to Do Not Track signals and does not use advertising or tracking across unrelated websites.
Email and your choices. Emailing the contact below shares your address, message, and any attachments with the editor and the email services that deliver and store them. They are used to respond and address the issue. You may request access, correction, or deletion of your correspondence at the same address; applicable law determines your rights. Please avoid sending sensitive personal information. Service providers may process information outside your country.
If a related record is copied into Cloudflare KV, that copy is used only to manage the issue and has a one-year retention policy. This period does not cover the original email or copies held by email providers.
Citation and reuse
Section titled “Citation and reuse”Cite a page by its title, BlackHole.org, URL, and access date. For an archived version, include its edition identifier and archive link.
Original site content, code, and data use the MIT License. Third-party material retains its stated rights. The working repository and source files are private; the license does not promise access to them.
Accessibility
Section titled “Accessibility”The site supports keyboard navigation, alternative text, adjustable formula images, and responsive layouts. Coverage varies; no independent accessibility certification is claimed. Report a barrier with the page URL and, if useful, your browser or assistive technology.
Contact
Section titled “Contact”For errors, accessibility issues, or privacy requests, email renphysics@blackhole.org. Include the relevant page URL and enough detail to understand the issue.