message: Don't just bug out if someone uses the 'from' command to request a frame which doesn't exist.
diff: @@ -1973,7 +1973,7 @@ class EtTerminal extends ThemeableElementBase implements CommandPaletteRequestTy
  data = this.getFrameContents(frameId);
  }
  // FIXME this should be binary safe and send metadata like mimetype and charset.
  - const lines = data.split("\n");
  + const lines = data == null ? [] : data.split("\n");
  let encodedData: string = "";
  lines.forEach( (line: string) => {
  const utf8line = utf8.encode(line);
  