leaktrace{
    require './AlmostEmpty.pm';
} -verbose;
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And it shows:

leaked SCALAR(0xa6a8a0) from ./3.pl line 7.
   6:leaktrace {
   7:    require './AlmostEmpty.pm'
   8:} -verbose;
SV = PV(0xa4ac20) at 0xa6a8a0
  REFCNT = 1
  FLAGS = (POK,pPOK)
  PV = 0xebe6e0 "./AlmostEmpty.pm"\0
  CUR = 16
  LEN = 24
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So, the leaked scalar contains the required file name. Why is that? Let's read the documentation:

These SVs include global variables and internal caches. For example, if you call a method in a tracing block, perl might prepare a cache for the method. Thus, to trace true leaks, no_leaks_ok() and leaks_cmp_ok() executes a block more than once.

And indeed, running no_leaks_ok shows:

ok 1 - leaks 0 <= 0
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So, it's probably some kind of a global variable. And indeed, compare the output with the one from

use Devel::Peek;
Dump $INC{'./AlmostEmpty.pm'};
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It shows the same scalar. So, it's just the entry in the %INC hash that prevents Perl from including the file once more if you require it again.

($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,
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