Debitto's outfit was one of them. I have come up with few sites where they sell the costume. They are easily found via Google or other search engines. But it's almost impossible to find good collection of reference pictures for Debitto's costume, because almost in every manga frame he is bent, stooped or partially blocked my Jasdero etc. When I was working with the costume I went trought many pictures to get the general view for the jacket. And it was actually really slow, some minor details were only drawn in few frames.
I have pointed out that I don't like manufactured costumes. One reason is the fact they usually lack the details. I thought I'd offer my alternative design for the jacket based on the manga illustrations. I came up with the cut, because in manga I didn't find any images with vertical seams. It's quite commonly used in leather jackets, which I think is the right material for Jasdero and Debitto.
I also gave my imagination a chance while choosing the fastening. One alternative could be poppers or buttons and over them would be overlapping piece of fabric to hide them. (Please, if anyone know what's it called officially, send a message!) I thought it would be natural to use a zipper, because there is one in Jasdero's vest. The other thing was the patches. I really don't know what they portray. In the sleeve there might be some kanji, but I'm not sure. Also the attachment in the collar might be with two poppers. It varied between references. The lenght of the jacket is over-knee. The way Debitto wears the jacket, hanging it over his shoulders makes it look like it reaches the knees. I came up with the other stichings to make the jacket look like a real deal, but only visible one in the references were the one on the hem. It's placed roughly three centimeters from the hem.
I hope this is useful to anyone who is going to sew the costume!
If you want to more detailed information about the jacket, leave a comment!