#actions /* 0,1,0,0 */
.words /* 0,0,1,0 */
It's a coding language.
The two lines are snippets that won't work on their own.
It's a stylesheet language.
It relates to an aspect of CSS which many people find confusing.
The numbers in the comments are there to help you, but they merely make other stuff more obvious.
Why was the BEM naming convention created?
It's about specificity.