When you look at questions currently tagged chebyshev-function, you will see questions from various areas there. (Number theory, Chebyshev polynomials, Chebyshev inequality,...) The tag-info for this tag is currently empty.
My first guess would be that this tag is supposed to be used for questions about Chebyshev functions such as $\vartheta(x)$ and $\psi(x)$, which are used in analytic number theory. (But there might be also some other meanings of this term I am unaware of.)
I think that it would be good to:
- Agree what this tag should be used for.
- Fill in the tag-excerpt and tag-wiki, explaining when the tag should be used.
- Clean up this tag. (Remove the tag from the questions belong there. Add the tag to the questions about Chebyshev functions.)
- If incorrectly tagged questions will keep appearing even after the tag-wiki is added, we might also create a comment template explaining correct usage of this tag.
But I wanted to get some input from other community members first.
I searched a bit whether this tag has already been discussed here on meta. The only thing I found was a mention of this tag in this answer:
Cautionary tale: chebyshev-function is full of questions about Chebyshev-whatever, but not -function. At a glance, I have not found a single question about actual Chebyshev functions there. It is not unusual for rarely-used tags with few followers to degenerate into such a mess.
I have also started retagging questions which do not belong here, see this list. They are mostly about Chebyshev polynomials and Chebyshev inequality. Since I am not very familiar with these two topics, some people with more experience in these areas might have a look at those questions and choose better tags, if needed.
Of course, if there is support for the suggestion to get rid of the tag entirely - as suggested in the AlexR's answer - this still can be done. (Although in that case we will have remove the tag-wiki, since the tags having tag-wiki are not removed from the system.)