You might want to consider changing some of your examples so that they don't lie on edge cases (that way it's more obvious what's happening). For example...

while (<DATA>)
{
  print if 2 .. 3;
}
[download]

...might be more instructive as...

while (<DATA>)
{
  print if 2 .. 4;
}
[download]

Likewise for ...

while (<DATA>)
{
  print if 1 .. /end/;
}
[download]

...and...

while (<DATA>)
{
  print if 2 .. /end/;
}
[download]