Missing icon whitespace trimming note

### MDN URL

https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/action

### What specific section or headline is this issue about?

_No response_

### What information was incorrect, unhelpful, or incomplete?

Safari trims the whitespace around `action` icons. This is often unknown to developers.

### What did you expect to see?

A note stating the Safari whitespace trimming behaviour.

### Do you have any supporting links, references, or citations?

_No response_

### Do you have anything more you want to share?

_No response_

### MDN metadata

Page report details

* Folder: `en-us/mozilla/add-ons/webextensions/manifest.json/action`
* MDN URL: https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/action
* GitHub URL: https://github.com/mdn/content/blob/main/files/en-us/mozilla/add-ons/webextensions/manifest.json/action/index.md
* Last commit: https://github.com/mdn/content/commit/8a74d8feac267c1ddc37a4a8bc61e9aa8db75b12
* Document last modified: 2026-03-22T01:55:43.000Z

@patrickkettner @xeenon FYI