Steps to replicate the issue (include links if applicable):

• While logged out, go to an edit screen on Japanese Wiktionary or Japanese Wikipedia, and be asked to solve captcha. (You don't need to solve it to experience the issue - it's just that the same issue does not happen to me on sites that doesn't always require captcha, such as Commons.) Example: https://ja.wiktionary.org/w/index.php?title=jipul&action=edit

What happens?:
The message box that contains the content of MediaWiki:Anoneditwarning includes a triangular icon from codex icons.

What should have happened instead?:

Previously the triangular icon was not there.

Is this new styling introduced by accident? If so, it should be undone. If intended, a Tech News entry informing of the change would be helpful.

Other information (browser name/version, screenshots, etc.):

Modules loaded:

RLSTATE = {
    "user.options": "loading",
    "ext.wikiEditor.styles": "ready",
    "mediawiki.action.edit.styles": "ready",
    "mediawiki.editfont.styles": "ready",
    "mediawiki.interface.helpers.styles": "ready",
    "oojs-ui-core.styles": "ready",
    "oojs-ui.styles.indicators": "ready",
    "mediawiki.widgets.styles": "ready",
    "oojs-ui-core.icons": "ready",
    "codex-styles": "ready",
    "ext.confirmEdit.fancyCaptcha.styles": "ready",
    "skins.vector.styles.legacy": "ready",
    "ext.charinsert.styles": "ready",
    "ext.visualEditor.desktopArticleTarget.noscript": "ready",
    "codex-search-styles": "ready",
    "ext.uls.interlanguage": "ready",
    "ext.wikimediaBadges": "ready"
};

I also noticed something else that might or might not be related. On sites where this does not happen, such as Meta, the triangular icon appears when I click the text area.
https://commons.wikimedia.org/w/index.php?title=Commons_talk:Welcome&action=edit
I'm happy to report it separately, if unrelated.