Questions about how to retrieve the existing data in the database

[jozhi]

I am a beginner in leveldb and I found a magical situation.

I used various methods to retrieve the stored data. In the end, I was surprised to find in an issue that the option of createKeyStream could use leq as the retrieval condition. I was shocked at that time. Because I have never experienced this way to learn a new technology, I need to come from other unofficial channels for the parameters that are not indicated in the official document but are actually available.
My question now is, how many of these parameters are hidden in other weird places that we need to rely on God's guidance to find them?

[vweevers]

What do you mean by leq? If you mean the lte option, that is documented.

[jozhi]

What do you mean by leq? If you mean the lte option, that is documented.

I'm talking about this query parameter
db.createKeyStream({ leq: "" })

[vweevers]

That's not supported by any module under the Level org. I have not seen it in the wider ecosystem either.