Finalize release notes for Firefox 154

[pepelsbey]

Description

Updates pages for Firefox 154 release (August 18, 2026).

• Removed active status from Firefox 153
• Updated Firefox 154 to (Stable)
• Updated Firefox 155 to (Beta)
• Created a new Nightly page for Firefox 156

Note

It successfully picked up the new schedule from whattrainisitnow.com:

• August 18th
• September 1st
• September 15th

[github-actions]

Preview URLs (4 pages)

• /en-US/docs/Mozilla/Firefox/Releases/153
• /en-US/docs/Mozilla/Firefox/Releases/154
• /en-US/docs/Mozilla/Firefox/Releases/155
• /en-US/docs/Mozilla/Firefox/Releases/156

Flaws (1)

Note! 3 documents with no flaws that don't need to be listed. 🎉

Found an unexpected or unresolvable flaw? Please report it here.

URL: /en-US/docs/Mozilla/Firefox/Releases/153
Title: Firefox 153 release notes for developers
Flaw count: 1

• broken_links:
  • Link /en-US/docs/Web/JavaScript/Reference/Statements/import/source doesn't resolve

External URLs (5)

URL: /en-US/docs/Mozilla/Firefox/Releases/154
Title: Firefox 154 release notes for developers (Stable)

• https://whattrainisitnow.com/release/?version=154 (1 time) (Note! This may be a new URL 👀)

---

URL: /en-US/docs/Mozilla/Firefox/Releases/155
Title: Firefox 155 release notes for developers (Beta)

• https://whattrainisitnow.com/release/?version=155 (1 time) (Note! This may be a new URL 👀)
• https://www.firefox.com/en-US/channel/desktop/ (1 time) (Note! This may be a new URL 👀)

---

URL: /en-US/docs/Mozilla/Firefox/Releases/156
Title: Firefox 156 release notes for developers (Nightly)

• https://whattrainisitnow.com/release/?version=156 (1 time) (Note! This may be a new URL 👀)
• https://www.firefox.com/en-US/channel/desktop/ (1 time) (Note! This may be a new URL 👀)

[dipikabh]

Looks good. Thank you!