Row 9 has been highlighted in brown indicating that the program has spotted a row unique mention on the line below the board, repeated here:
row 9: 5 occurs uniquely, (9,5)=[5,9,7] now 5
On row 9, 5 is only mentioned as a possibility in the middle cell (the 5th). Since 5 must occur exactly once in row 9, (9,5) must be 5. The other possibilites in (9,5), namely 7 and 9 (highlighted in red), can be simply removed.
[This heuristic is quite different from the previous unique row/column heuristic - which cannot place a 5 in this situation. Looking at the larger picture, note that 5 has been placed for columns 1, 2, 3, 4, 6 and 9, taking rows 2, 3, 4, 5, 6 and 8, respectively. This leaves rows 1, 7 and 9 available. 5 also has not be determined for columns 5, 7 and 8. Together, available rows [1,7,9] and columns [5,7,8] leave many possible row/column combinations for 5.]