The most possible explanation is this:

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1.yet (UNTIL NOW): still; until the present time:

E.g: I haven't spoken to her yet.
E.g: He hasn't finished yet.
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2.yet (DESPITE THAT): (and) despite that; used to add something that seems surprising because of what you have just said:

E.g: simple yet effective
E.g: He's overweight and bald, (and) yet somehow, he's incredibly attractive

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3.FORMAL as yet until and including this time: We haven't needed extra staff as yet, but may do in the future.

E.g: No ambulances had as yet managed to get across the river

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4.Have yet to: If you have yet to do something, you have not done it:

E.g:: They have yet to make a decision

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5.Yet (more): used to add emphasis to words such as another and again, especially to show an increase in amount or the number of times something happens:

E.g: Rachel bought yet another pair of shoes to add to her collection.
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6.yet (EVEN NOW):even at this stage or time: We could yet succeed - you never know.

E.g: You might yet prove me wrong

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So, as you can see the "yet" is going to be used at the end of the sentence if the idea is "yet (UNTIL NOW): still; until the present time". Such as the very first explanation!

I took this form the Cambridge dictionary, I hope I shed some light upon this subject.