The Réti search was an experimental feature when I started systematic endgame analysis. It has since been overtaken by more powerful tools (not included in the ChessSuite) and it is likely to be removed in the next release.

The Réti search can be found in the menu Info -> Experimental -> New Reti search. This will start the following dialog.

Every line in this table represents a condition that can be applied to an ending K+P vs K+P (the material of Réti's famous study). The conditions can be set one after the other, but it is much more convenient to set all at once by a given position (see menu Initialize). So, with Réti's position we get the following settings with ease:

Once again one can vary the requirements or start the search immediately. The result will be stored in a PGN file with all fragments that fulfill the requirements. For the given example one gets three starting positions, one being Réti's position, of course, and two variants thereof. Here the result is shown in the PGN file browser.

So, by means of the Réti search one can find certain interesting positions among all positions with K+P vs K+P. The number of these positions is about 3.8 million, without symmetrical ones, and I think that possible up to 100 of them are endgame studies.