extensions/markdown-language-features/src/security.ts/ExtensionContentSecurityPolicyArbiter/getSecurityLevelForResource
class ExtensionContentSecurityPolicyArbiter:	public getSecurityLevelForResource(resource: vscode.Uri): MarkdownPreviewSecurityLevel {
		// Use new security level setting first
		const level = this.globalState.get<MarkdownPreviewSecurityLevel | undefined>(this.security_level_key + this.getRoot(resource), undefined);
		if (typeof level !== 'undefined') {
			return level;
		}

		// Fallback to old trusted workspace setting
		if (this.globalState.get<boolean>(this.old_trusted_workspace_key + this.getRoot(resource), false)) {
			return MarkdownPreviewSecurityLevel.AllowScriptsAndAllContent;
		}
		return MarkdownPreviewSecurityLevel.Strict;
	}