Create 2025-08-07-expanded-link-isolation.mdx

[petecodes]

needs to upload this to: https://github.com/cloudflare/cloudflare-docs/tree/production/src/assets/images/changelog/email-security

with this file:
https://drive.google.com/file/d/1p4gfcPHsogMgOxua1N4HBBWg28_XsL7B/view?usp=drive_link

Summary

Screenshots (optional)

Documentation checklist

• Is there a changelog entry (guidelines)? If you don't add one for something awesome and new (however small) — how will our customers find out? Changelogs are automatically posted to RSS feeds, the Discord, and X.
• The documentation style guide has been adhered to.
• If a larger change - such as adding a new page- an issue has been opened in relation to any incorrect or out of date information that this PR fixes.
• Files which have changed name or location have been allocated redirects.