Garbled characters occur in UDT Debug Window

Japanese is set for “name” in manifest.json.

{
  "id": "Test-9vimoa",
  "name": "最初のプラグイン",
  "version": "1.0.0",
  "main": "index.html",

At this time, the title bar of DevTools is displayed in Japanese, but the characters at the bottom (the area surrounded by the red oval) are garbled.
Since there is no actual harm, please fix it as a feature-request.

thanks for reporting. Created a ticket [UXP-21785] for tracking this internally