What is this tensor operation called?

This operation is called Kronecker Product. Here is the Wikipedia's link : https://en.m.wikipedia.org/wiki/Kronecker_product#:~:text=In%20mathematics%2C%20the%20Kronecker%20product,resulting%20in%20a%20block%20matrix.&text=The%20Kronecker%20product%20is%20named,to%20define%20and%20use%20it.

As indicated by @Nitin Tomar, it is a Kronecker product, and your $?$ point has to be replaced by the classical symbol $\otimes$ :

$$\begin{pmatrix} a & b & c \\ d & e & f \\ g & h & i \\ \end{pmatrix} \otimes M = \begin{pmatrix} aM & bM & cM \\ dM & eM & fM \\ gM & hM & iM \\ \end{pmatrix}$$

Kronecker product has many nice properties, for example regarding eigenvalues and eigenvectors, but not in general commutativity.

As you address programming languages, Matlab for example has a special function called "kron" for this operation :

 L=[a,b,c
    d,e,f
    g,h,i];
 M=[j,k
    l,m];
 kron(L,M)

Related : you can also define a Kronecker $\oplus$ operation.