I'm curious on how one would go about helping maintain an addon that the owner is no longer maintaining. The addon owner has mentioned that they no longer wish to maintain this addon, and I cannot seem to get ahold of the owner. I have fixed many issues for current patch. Is there anything I can do to get this addon updated? I will help maintain it if at all possible, since I am an avid user of it and hope to see it carry on.
Phanx is listed as the current maintainer of Grid, and the last update was on May 11, 2018. That was only four months ago. She can more easily be reached by sending her a message on Wowinterface. This is her user page over there. If she is wiling to accept your updates, or even take over Grid, then click the Report Project link and follow the prompts. Provide all the information possible about your attempts to talk to Phanx, permissions or not to take over the addon, and whatever else is appropriate when you report it.
Then a Curseforge file moderator will look into the situation and take it from there.
Just want to chime in and say to please not contact us; projects are the sole responsibility of their owners, and we will not transfer them under any circumstances. We used to do so if there hadn't been updates in a couple of years and the license allowed for forks, but we ended that practice roughly three years ago after a rash of folks came back to find they no longer controlled their own project.