All Octicons
no-entry-fill
React
import {NoEntryFillIcon} from '@primer/octicons-react' <NoEntryFillIcon size={12} />
Rails
<%= render(Primer::Beta::Octicon.new(:"no-entry-fill", size: :xsmall)) %>
Jekyll
{% octicon no-entry-fill height:12 %}
Figma
This icon is called no-entry-fill-12
in Primer's Octicons library.