The frame (sides) are not rabbetted for the glass in this plan. The sides are built, the molding is applied, it's turned upside down and the glass is put in from the back. Then you add the hot glue to hold the glass in place once it upright. The glue will be removable with a chisel or scraper or razor blade if you have to get the glass out.Yup that's the one I found. The wood is routered out to make a groove for the glass and then a decorative piece over that to really secure the glass. If the glass gets broken you have to destroy the frame to replace.
The only "groove" you have to cut is for the wood back to make it flush with the rails. You can clearly see this in the plan.
Maybe this will help. Blue is for the glass, green for the glue and brown for the bottom. Sorry about the low quality drawing, I'm doing this on my phone.