Where can I find the "Burning Summit" Grenade?

I am looking for this unique grenade to do some testing with after seeing a Tweet and News article about it. After spending some time browsing reddit, google, and the forums, I have not found a single indication of how to obtain the Burning Summit.

Does anyone have an idea of how I can get my hands on one?

Seems some have gotten it in Social mail attachments. Comes attached to a mail from Tyreen.

Any idea what triggered the mail from her?

Did a bit of looking and came up empty on that one. I haven’t gotten it myself (just sharing info found online and confirmed with screenshots).

I think it comes from completing a lot of CoV gun challenges. I got it in the mail when I was using a CoV legendary pistol while farming.

I don’t use CoV anything and while sitting around afk I got a mail from Tyreen with this Grenade mod, wanted to see what triggered it but no clue at this point but I’m not complaining, haven’t tried it out yet though so gonna see how good it can be