extensions/markdown-language-features/preview-src/csp.ts/CspAlerter/constructor
class CspAlerter:	constructor(
		private readonly settingsManager: SettingsManager,
	) {
		document.addEventListener('securitypolicyviolation', () => {
			this.onCspWarning();
		});

		window.addEventListener('message', (event) => {
			if (event && event.data && event.data.name === 'vscode-did-block-svg') {
				this.onCspWarning();
			}
		});
	}