Positions 8238  Stoc  Rebe  Rebe  Rebe  Rebe  Rebe  Rebe  Rebe  
Stockfish 10   ----- 43.92 47.54 49.75 52.74 55.10 55.89 58.91  
Rebelfish 0.00 43.92 ----- 85.37 78.96 72.51 67.87 63.64 53.29  
Rebelfish 0.05 47.54 85.37 ----- 85.32 79.63 74.62 70.38 59.59  
Rebelfish 0.10 49.75 78.96 85.32 ----- 85.57 80.52 76.45 65.43  
Rebelfish 0.15 52.74 72.51 79.63 85.57 ----- 87.59 83.09 71.96  
Rebelfish 0.20 55.10 67.87 74.62 80.52 87.59 ----- 88.10 76.63  
Rebelfish 0.25 55.89 63.64 70.38 76.45 83.09 88.10 ----- 80.60  
Rebelfish 0.50 58.91 53.29 59.59 65.43 71.96 76.63 80.60 ----- 

1. Engine {Stockfish 10  } and {Rebelfish 0.50} show a similarity of 58.91%
2. Engine {Stockfish 10  } and {Rebelfish 0.25} show a similarity of 55.89%
3. Engine {Stockfish 10  } and {Rebelfish 0.20} show a similarity of 55.10%
4. Engine {Stockfish 10  } and {Rebelfish 0.15} show a similarity of 52.74%
5. Engine {Stockfish 10  } and {Rebelfish 0.10} show a similarity of 49.75%
6. Engine {Stockfish 10  } and {Rebelfish 0.05} show a similarity of 47.54%
7. Engine {Stockfish 10  } and {Rebelfish 0.00} show a similarity of 43.92%

Legenda
1. A similarity percentage of over 70% means that engine is a clone with only a few changes.
2. A similarity percentage between 65-69% is considered a clone with considerable changes.  
3. A similarity percentage between 60-64% is called a derivative work.
4. A similarity percentage between 55-59% is the grey area, likely a derivative work but impossible to conclude for sure.
5. A similarity percentage between 50-54% Still a bit high, impossible to draw a conclusion.

Limitation - Similarity Tester can only proof a clone or a derivative work, it can not conclude the opposite. 
An engine might score a similarity percentage of 40% (an indication of a very original engine) it still can 
be a derivative work. There are some tricks to fool Similarity Tester without much elo loss.