/usr/share/tcltk/critcl-app3.1.8/pkgIndex.tcl is in critcl 3.1.9-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1
package ifneeded critcl::app 3.1.8 [list source [file join $dir critcl.tcl]]