The linked Twitter post just rotated the original video from portrait to landscape. It looks like the Twitter account that posted the original video 4 hours ago (@VasutTomas0423) was created today and has only two posts. The first post just has the portrait video and some Czech text. Per Google Translate: "First time joining Searching for the source of this video. My fellow researcher said he received this video from another colleague on Telegram."
Someone then asks: "what channel?" and the OP responds (in English): "I asked. There may be a time difference between my friend and me."
So... about as sketchy and unattributed as can possibly be.
Edit to Add:
More perspective from another Twitter account (Malý vědec @malyvedec):
"That's a very strange account. It pretends to be Czech with a Czech author's name, but the text was definitely not written by a native speaker, but rather by a bot or someone with a bad translator."
Source isn't completely clear but rumors are that it's out of China. Obviously should be taken with a grain of salt, if it's real others should be coming
Someone then asks: "what channel?" and the OP responds (in English): "I asked. There may be a time difference between my friend and me."
So... about as sketchy and unattributed as can possibly be.
Edit to Add:
More perspective from another Twitter account (Malý vědec @malyvedec): "That's a very strange account. It pretends to be Czech with a Czech author's name, but the text was definitely not written by a native speaker, but rather by a bot or someone with a bad translator."