C++ translation: change int to unsigned in pair type.
The description states: "...test cases ensure that the number of people in the bus is always >= 0". Also, the function returns unsigned.
Therefore, int in pair type should be replaced with unsigned to avoid implicit conversions.

Solution:
unsigned number(const std::vector<std::pair<unsigned, unsigned>>& busStops)

Tests:
using V = std::pair<unsigned, unsigned>;

C#

In Solution section: typo in the method comment : "// retrun" > "// return".

JavaScript translation that enforces in-place mutation

the kata would be made more interesting if it enforced in-place mutation of the list instead of allowing pure funtions to pass (that circumvents the bug entirely)

I suggest adding test cases where the date of birth is exactly n years before the current date and is in a leap year

please consider improving the description by providing more specific details. the current instructions are unclear and could be refined for better understanding.

You will be provided with two object arrays.

wording is too C#-specific (and is probably not an appropriate type for C#)

additionally, description does not state that the given positions are for a knight and a bishop, the description thus does not state what the problem to solve is. those pieces could be pawns for all I know from reading the description

it is also a very strange and indirect way of stating that only two pieces exist on the board

It could instead read something along the lines of:

You will be provided with the positions of a knight and a bishop on a board that is otherwise empty (e.g. [4, "C"] and [6, "D"]).

The second value in the first pair in the array is 0, since the bus is empty in the first bus stop.

Not the case for Ruby

Groovy translation

I feel like the method name for the Groovy translation should be whatIsTheTime in camelCase instead of PascalCase

EDIT: I also got it to work by including an additional default (parameterless) constructor.

I had a lot of issues with this one trying to use a constructor to initialize the name property.

i.e, I had to remove:
public PersonEventArgs(string name)
{
Name = name;
}

And pass the name by doing:

ContactNotify?.Invoke(this, new PersonEventArgs(){Name=name});

Any attempt to pass name resulted in a CS7036 error depicting there was no parameter 'name' of 'PersonEventArgs.PersonEventArgs(string)'

C#: method name should be PascalCase (Please refer to implementation of backward compatibility here )

Actual and expected are swapped in PHP