src/vs/workbench/api/common/extHostCustomEditors.ts/ExtHostCustomEditors/$onMoveCustomEditor
class ExtHostCustomEditors:	async $onMoveCustomEditor(handle: string, newResourceComponents: UriComponents, viewType: string): Promise<void> {
		const entry = this._editorProviders.get(viewType);
		if (!entry) {
			throw new Error(`No provider found for '${viewType}'`);
		}

		if (!(entry.provider as vscode.CustomTextEditorProvider).moveCustomTextEditor) {
			throw new Error(`Provider does not implement move '${viewType}'`);
		}

		const webview = this._extHostWebviewPanels.getWebviewPanel(handle);
		if (!webview) {
			throw new Error(`No webview found`);
		}

		const resource = URI.revive(newResourceComponents);
		const document = this._extHostDocuments.getDocument(resource);
		await (entry.provider as vscode.CustomTextEditorProvider).moveCustomTextEditor!(document, webview, CancellationToken.None);
	}