use strict;
use warnings;
use 5.010;

# from documentation:
# ... and each of these:

print join(':', split(//, 'abc', 3)), "\n";
print join(':', split(//, 'abc', 4)), "\n";

# produces the output a:b:c .

say $^V;
say $^O;

__DATA__
output:
a:b:c
a:b:c:
v5.30.1
[download]

In the second call there is an extra empty string. I am using Windows 10.