Error Above Page, Can't Find Where to Contact a Dev

Edit: The op helped me fix 2 of the problems I have had, so I will change this to 4 star. Still not 5 because he only helped me disable to error notification, not remove the error. Great props for the time it took him to respond (like 10 minutes, and it’s only one guy, so that’s really good.)

For those wondering, and incase others have the same problem, he had me add

.xdebug-error {
display: none;
}

to the end of my style.css in my theme.

I cannot find where to contact a dev for this plugin, so I have decided to post here. On my website, this pops up above the content: https://puu.sh/bKwL6/5cc992462c.png

My website is archez.tv/forums and these are my plugins. I think it might be a conflicting plugin?