/usr/lib/tcltk/expect5.45/pkgIndex.tcl is in expect 5.45-5ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 | if {![package vsatisfies [package provide Tcl] 8.6]} {return}
package ifneeded Expect 5.45 \
[list load [file join /usr lib libexpect.so.5.45]]
|