That is a simple moving average applied to rsi (or whatever average is chosen out of the possible 4 types - none centered TMA)
See the comparison (blue line is the sma 26 - used that to match the default settings of that indicator) - they are exactly the same
As I told : whoever named it centered TMA is either having no idea what is he talking about or he was simply lying to call attention to something that has as much common with centered tma as my left shoe has with floating in the ocean