APEL stands for "A Portable Emacs Library" and contains these modules:
  apel
     - alist: utility for Association-list
     - calist: utility for condition tree and condition/situation-alist
     - filename: utility to make file-name
     - install: utility to install emacs-lisp package
     - mule-caeser: ROT 13-47-48 Caesar rotation utility
     - path-util: utility for path management or file detection
  emu
     - broken: provide information of broken facilities of Emacs.
     - invisible: provide features about invisible region
     - mcharset: provide MIME charset related features
     - pces: provide portable character encoding scheme features
     - pccl: utility to write portable CCL program
     - pcustom: provide portable custom environment
     - poe: emulation module for basic functions and special forms/macros
     - poem: provide basic functions to write portable MULE programs
     - static: utility for static evaluation