5103 Waiver Review?

[TiredCoastie]

Have seen a couple of posts about this but maybe it's my neurologic condition that's not letting me understand this...

Ebennies today changed for my latest claim, a reconsideration of the VA's denial of service connection of a couple of serious medical conditions as well as my hearing loss plus a request to increase the disability rating for osteoarthritis. After three months as of yesterday, the claim moved from "under review" to "gathering evidence." A development letter is apparently being sent. Ebennies does not list any information requested of me. However, for information requested of third parties, ebennies says that a "5103 Waiver Review" has been requested with a month due date.

What is a 5103 waiver and why would it need to be reviewed?

Or is this just gov-speak?

Having read through what's posted on the web, it seems as if it could be either. E.g.

http://www.vfwofwa.org/Announcements/news/disability_claims_1.pdf

I can understand if it's just a way of asking me if I've got more information to transmit...and I may having just been hospitalized for yet another TIA...but why send the review out to a third party? Could that third party be the VSO which represents me for my claim?

Thanks for everyone's help!