This is a great question, and it led me down a bit of a rabbit hole. This kind of clause is called a Gapless Relative Clause. The sentence could be written as you have it, or with "I don't know what it is" - the "it" is called the Resumptive Pronoun which are "common in spoken English but are officially ungrammatical".
The Wikipedia article has a similar example:
In other cases, the resumptive pronoun is used to work around a syntactic constraint:
They have a billion dollars of inventory that they don't know where it is.
In this example, the word it occurs as part of a wh-island. Attempting to extract it gives an unacceptable result:
*They have a billion dollars of inventory that they don't know where ___ is.
"Resumptives are non-standard, but in such cases they're much better than their gapped counterparts, which people usually find incomprehensible, or at least very hard to comprehend."
So basically, your original sentence is "unacceptable"/"incomprehensible", but adding "it" would be grammatically incorrect but easier to understand. Best bet is probably to totally rephrase the sentence as others have suggested.
I signed up on two small kbin instances (kbin.lol and fediverse.boo) to check it out. Both have since shut down. The first was due to similar complaints; the second just disappeared as far as I know.
I was just thinking earlier today, games could probably use AI to seamlessly work the player's name into dialog. They would still hire voice actors, but insert whatever name the player chooses into the lines where it is mentioned. I feel like this isn't too far away.
That one's easy - in The Voyage Home, when they go back to 1986, a busload of people saw Spock neck pinch a guy playing loud music, and Kirk said his name right afterward. Word spread about this and it became a popular urban legend, enough so that the Beastie Boys referenced it in a song 12 years later.
You're right, there wasn't. I didn't read the article at first since I thought the title was clickbait, but it seems like they're actually saying the ratings were lower than any debate in 2015 or later. They just phrased it in a confusing way.
Oh, hi Worf