# What is the significance of “(k=v)”?

When one uses C-c C-e to insert an environment such as enumerate in AUCTeX , one is presented with the prompt (Optional) Options (k=v): in the minibuffer.

I know that this is asking for options for the environment, but could someone please explain what the (k=v) means? It appears in certain environments' options prompts (e.g. enumerate, itemize), but not in others (e.g. figure, tabular). I couldn't find any explanation online. My AUCTeX version is 11.89, if that's important.

• k=v stands for key=value. – NickD Mar 28 '18 at 16:35

Some environments take options in the format option_name=value. For example, if you use the enumitem package, which replaces the built-in enumerate environment, you can get an enumeration using letters for the labels (in place of numbers) with the following code:
\begin{enumerate}[label=\alph*]

AuCTeX must have a list of which commonly used environments take options in the k=v format (like the label=\alph* above).