Raised area on floor

Remembrance

I have 260 Express Cruiser and am planning to replace the carpet in front of the frig. When I step down into the cabin and look forward there is a very noticable bump in the LH corner at the step up to the table. Is this unique to my boat? Is it common to others? Does anybody know what it is? I would like to understand what it is before I tear up the floor.