Do line numbers in a code theme need to meet WCAG AA contrast?

We’re designing a custom code theme which displays line numbers, and we’re having some internal debate whether these line numbers need to meet WCAG AA contrast guidelines? They’re not the main body text, but neither are they the acceptable exceptions outlined in the guidelines. My guess is that they should meet contrast guidelines, but I’ve seen many themes where the line numbers are very low contrast.

Could anyone point me to some research/guidelines on this?