Edit: /usr/share/tcl8.6/opt0.4/pkgIndex.tcl (607B)
# Tcl package index file, version 1.1
# This file is generated by the "pkg_mkIndex -direct" command
# and sourced either when an application starts up or
# by a "package unknown" script. It invokes the
# "package ifneeded" command to set up package-related
# information so that packages will be loaded automatically
# in response to "package require" commands. When this
# script is sourced, the variable $dir must contain the
# full path name of this file's directory.
if {![package vsatisfies [package provide Tcl] 8.2]} {return}
package ifneeded opt 0.4.6 [list source [file join $dir optparse.tcl]]