what does "importance" attribute mean in the results of E()?

Hi, I am running E(a) on a graph object (ie. a) and getting a vector of edge sequence. When I go to E(a)$importance, I see a vector of numbers. What does this vector of numbers mean?

Thank you!

As far as I know, $importance doesn’t exist when creating a new graph. Maybe you can show the code for reproducibility.

It is an edge attribute. Each edge has an assigned number. Either you added this attribute yourself, or more likely you imported a graph from a file. In that case you should ask the author of that file about the meaning of these numbers.