added experimental note for pseudo-elements after pseudo-elements

[dletorey]

Description

• added experimental note for Firefox
• added experimental note to the Firefox 138 release page

Motivation

• Working on issue #38910

Related issues and pull requests

• N/A

[github-actions]

Preview URLs

• /en-US/docs/Mozilla/Firefox/Experimental_features
• /en-US/docs/Mozilla/Firefox/Releases/138

Flaws (4)

URL: /en-US/docs/Mozilla/Firefox/Experimental_features
Title: Experimental features in Firefox
Flaw count: 3

• macros:
  • Macro produces link /en-US/docs/Web/HTML/Element/details which is a redirect
  • Macro produces link /en-US/docs/Web/HTML/Element/details which is a redirect
  • Macro produces link /en-US/docs/Web/HTML/Element/input which is a redirect

---

URL: /en-US/docs/Mozilla/Firefox/Releases/138
Title: Firefox 138 for developers
Flaw count: 1

• macros:
  • Macro produces link /en-US/docs/Web/HTML/Element/details which is a redirect

External URLs (2)

URL: /en-US/docs/Mozilla/Firefox/Experimental_features
Title: Experimental features in Firefox

• https://bugzil.la/1953557 (1 time) (Note! This may be a new URL 👀)

---

URL: /en-US/docs/Mozilla/Firefox/Releases/138
Title: Firefox 138 for developers

• https://bugzil.la/1953557 (1 time) (Note! This may be a new URL 👀)

(comment last updated: 2025-04-28 10:51:09)

[estelle]

drive by comment:

There are a few other times pseudo-elements on pseudo-elements are mentioned. I thought there was a note on it somewhere, which I can't find, but did find these while looking for it:

• nested pseudo elements
• pseudo-element on a pseudo element

if ::first-letter is supported on ::details-content, pseudo-elements are already allowed on element-backed pseudo-elements.... so not sure the title is exact here. I was looking for a "tree-abiding pseudo-elements" note, but apparently that's not it.