This is Perl module PerlIO::fse.

INSTALLATION

PerlIO::fse installation is straightforward. If your CPAN shell is set up,
you should just be able to do

   $ cpan PerlIO::fse

Download it, unpack it, then build it as per the usual:

   $ perl Makefile.PL
   $ make && make test

Then install it:

   $ make install

DOCUMENTATION

PerlIO::fse documentation is available as in POD. So you can do:

   $ perldoc PerlIO::fse

to read the documentation online with your favorite pager.

Goro Fuji (gfx)