ibuffer-compressed-file-name-regexp

ibuffer-compressed-file-name-regexp is a variable defined in `ibuffer.el'.
Its value is

"\\.\\(arj\\|bgz\\|bz2\\|gz\\|lzh\\|taz\\|tgz\\|xz\\|zip\\|z\\)$"

Documentation:
Regexp to match compressed file names.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 24.1 of Emacs.