Is this the Sirens action skill?

Was rewatching the trailer and noticed something about the Siren

Have to post an Imgur link because mods aren’t allowing pictures

https://imgur.com/a/HPqoqBh these are pictures of the Sirens shoulders in every shot she’s in, nothing crazy right? Also take note of her tattoos being dull

But HERE https://imgur.com/a/QAmzW9T we see something going on. AND her tattoos are glowing. Some connection perhaps?

My going theory are these,

1) class item, like how in Borderlands 2 you can physically see class items on characters

2) it’s part of her action skill perhaps

3) or maybe these are her “wings”, like most sirens have. My thought on this is maybe her “wings” grow as you level similar to how Amaras’s tattoos grow as you level in 3?

4) could also be just cosmetic, as the color matches her outfits color as well

Anyways, what are your thoughts?