src/vs/workbench/api/common/extHostWebview.ts/ExtHostWebview/cspSource
class ExtHostWebview:	public get cspSource(): string {
		const extensionLocation = this.#extension.extensionLocation;
		if (extensionLocation.scheme === Schemas.https || extensionLocation.scheme === Schemas.http) {
			// The extension is being served up from a CDN.
			// Also include the CDN in the default csp.
			let extensionCspRule = extensionLocation.toString();
			if (!extensionCspRule.endsWith('/')) {
				// Always treat the location as a directory so that we allow all content under it
				extensionCspRule += '/';
			}
			return extensionCspRule + ' ' + webviewGenericCspSource;
		}
		return webviewGenericCspSource;
	}