Roundness of the hole, is as it says the tolerance referring to the permitted roundness of a hole.
The example shown states that the roundness is 0.03mm for a 10mm drill. Therefore the drilled hole must fall within a range of 10mm ±0.03mm.
As long as the hole is within 9.97~10.03mm then it is acceptable.
Min. (ø 9.97)
Max. (ø 10.03)