This is the content of sudoku_0_0-1-py3-none-any.whl. So when the (0,0) cell is 1, none of the cells in the same row, column and subgrid should be 1.

    Requires-Dist: sudoku_0_1 != 1
    Requires-Dist: sudoku_0_2 != 1
    Requires-Dist: sudoku_0_3 != 1
    Requires-Dist: sudoku_0_4 != 1
    Requires-Dist: sudoku_0_5 != 1
    Requires-Dist: sudoku_0_6 != 1
    Requires-Dist: sudoku_0_7 != 1
    Requires-Dist: sudoku_0_8 != 1
    Requires-Dist: sudoku_1_0 != 1
    Requires-Dist: sudoku_2_0 != 1
    Requires-Dist: sudoku_3_0 != 1
    Requires-Dist: sudoku_4_0 != 1
    Requires-Dist: sudoku_5_0 != 1
    Requires-Dist: sudoku_6_0 != 1
    Requires-Dist: sudoku_7_0 != 1
    Requires-Dist: sudoku_8_0 != 1
    Requires-Dist: sudoku_0_1 != 1
    Requires-Dist: sudoku_0_2 != 1
    Requires-Dist: sudoku_1_0 != 1
    Requires-Dist: sudoku_1_1 != 1
    Requires-Dist: sudoku_1_2 != 1
    Requires-Dist: sudoku_2_0 != 1
    Requires-Dist: sudoku_2_1 != 1
    Requires-Dist: sudoku_2_2 != 1

The constraints are going to be static and independent of the puzzle. So I expect they're encoded in the package dependencies. So for example version 1 of the package sudoku_0_0 will conflict with all of: version 1 of sudoku_[0-8]_0; version 1 of sudoku_0_[0-8]; version 1 of [012]_ [012].

Yeah they missed out the actual interesting bit from the readme...