Just seen and ad on Farcebook for a mini chain saw, the one in the filmed demo is a STIHL made unit, but when you go to the shop page to purchase the item shown for £29.99 it is a GTA 26 with no STIHL markings at all. Header says 2020 HOT SELLING-GTA 26 Battery-Powered Wood Cutter. For that price I expect it is a Chinese copy.
Interestingly when you pause the demo video, the demo screen goes black, so I recorded it with a screen recorder.