Add documentation for disabling GlyphIcons in Classic UI

docs/classic-ui/icons.md

@@ -31,10 +31,32 @@ Icons are shipped via `plone.staticresources`.
 See the file [package.json](https://github.com/plone/plone.staticresources/blob/master/package.json) of the package to get the actual version of the icons in Plone.
 
 
+(classic-ui-icons-disable-glyphicons-label)=
+
+## Disabling GlyphIcons
+
+Plone Classic UI does not use GlyphIcons by default in Plone 6, as Bootstrap Icons are the preferred icon set.
+However, in some projects or legacy setups, GlyphIcons may still be loaded or referenced through custom themes or add-ons.
+
+If you want to explicitly disable GlyphIcons to avoid loading unused assets or to prevent accidental usage, you can do so by removing or overriding the related resources.
+
+### Disable GlyphIcons in Classic UI
+
+Ensure that your theme or add-on does **not** include GlyphIcons CSS or resources.
+If GlyphIcons are loaded via custom Diazo rules, theme bundles, or legacy add-ons, remove those references.
+
+For example, remove any references similar to:
+
+```html
+<link rel="stylesheet" href="++plone++static/glyphicons.css" />
+```
+
+
 (classic-ui-icons-registration-label)=
 
 ## Registration
 
+
 Icons are registered in Plone's registry.
 This provides an option to customize the content type and Plone UI icons by overriding icons via XML.
 Plone ships with the following icon registrations by default.