/usr/share/calc/help/bit is in apcalc-common 2.12.4.4-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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    bit - whether a given binary bit is set in a value
SYNOPSIS
    bit(x, y)
TYPES
    x		real
    y		int
    return	int
DESCRIPTION
    Determine if the binary bit y is set in x.	If:
	     x
	int(---) mod 2 == 1
	    2^y
    return 1, otherwise return 0.
EXAMPLE
    ; print bit(9,0), bit(9,1), bit(9,2), bit(9,3)
    1 0 0 1
    ; print bit(9,4), bit(0,0), bit(9,-1)
    0 0 0
    ; print bit(1.25, -2), bit(1.25, -1), bit(1.25, 0)
    1 0 1
    ; p = pi()
    ; print bit(p, 1), bit(p, -2), bit(p, -3)
    1 0 1
LIMITS
    -2^31 < y < 2^31
LINK LIBRARY
    BOOL qbit(NUMBER *x, long y)
SEE ALSO
    highbit, lowbit, digit
## Copyright (C) 1999  Landon Curt Noll
##
## Calc is open software; you can redistribute it and/or modify it under
## the terms of the version 2.1 of the GNU Lesser General Public License
## as published by the Free Software Foundation.
##
## Calc is distributed in the hope that it will be useful, but WITHOUT
## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
## or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU Lesser General
## Public License for more details.
##
## A copy of version 2.1 of the GNU Lesser General Public License is
## distributed with calc under the filename COPYING-LGPL.  You should have
## received a copy with calc; if not, write to Free Software Foundation, Inc.
## 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
##
## @(#) $Revision: 30.1 $
## @(#) $Id: bit,v 30.1 2007/03/16 11:10:42 chongo Exp $
## @(#) $Source: /usr/local/src/cmd/calc/help/RCS/bit,v $
##
## Under source code control:	1994/10/21 02:21:30
## File existed as early as:	1994
##
## chongo <was here> /\oo/\	http://www.isthe.com/chongo/
## Share and enjoy!  :-)	http://www.isthe.com/chongo/tech/comp/calc/
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