What does it mean that a state belongin to a given irrep transforms like $Rx$, $Ry$ or $Rz$

The present question is related to [this other question](https://chemistry.stackexchange.com/q/166089/125277) I did few days ago.
Given a point group and the list of the irreps (see for example [here](https://www.webqc.org/symmetrypointgroup-oh.html)) the meaning of an irrep which transforms like $x$ or $x^2$ is clear to me.


Instead I do not understand what is meant when it is written that an irrep transforms like $Rx$.


Let me explain a bit better. Say that the group is the symmetry group o a crystal structure. It can be represented as a set of $3\times3$ matricies $M\_i$. These matrices can be used to transform the vector $v=(x,y,z)$. So I can clearly see how something which transforms like x would be affected: $v'=M\_iv$ and $v'=(x',y',z')$.
I can also assume that any function of $f(x,y,z)$, like $f(x,y,z)=x^2$ would be transformed like $f(x,y,z) \rightarrow f(x',y',z')$ (is this point true?). However I do not understand how $Rx$ would transform. It is not even a defined function, but a group of operations by itself.




$R\_x$ etc. are rotations about the indicated axis. See for example [this article in chem.libretexts](https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Book%3A_Symmetry_(Vallance)/01%3A_Chapters/1.14%3A_Character_Tables) or [this pdf](https://instruct.uwo.ca/chemistry/734b/Group%20Theory-Part%204%20Irreducible%20Representations%20and%20Character%20Tables.pdf)


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