This is 9libs, a package of Plan 9 compatibility libraries derived from
the X11 version of Rob Pike's editor, sam. The package consists of:

* libXg, an X11 implementation of Plan 9's libg graphics library.
  The library's declarations are in include/libg.h
* libframe, a library which implements rectangular text areas using
  libXg. Declarations are in include/frame.h
* libplan9c, a library which aims to provide implementations of some of
  the more general-purpose parts of the Plan 9 C library. This includes
  the libregexp library from recent sam distributions. Declarations
  are in include/u.h and include/libc.h, which are the first things
  included by Plan 9 C files. Declarations for the regular expression
  components of the library are in regexp.h.
* Documentation for the libraries, as manual pages in the doc directory.