/usr/share/xcrysden/Tcl/fs/ is in xcrysden-data 1.5.53-1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/xcrysden/Tcl/fs/FS_Main.tcl
/usr/share/xcrysden/Tcl/fs/FS_Multi.tcl
/usr/share/xcrysden/Tcl/fs/Makefile
/usr/share/xcrysden/Tcl/fs/bandselect.tcl
/usr/share/xcrysden/Tcl/fs/bandwidths.tcl
/usr/share/xcrysden/Tcl/fs/genFSInit.tcl
/usr/share/xcrysden/Tcl/fs/header.tcl
/usr/share/xcrysden/Tcl/fs/interpolate.tcl
/usr/share/xcrysden/Tcl/fs/tclIndex
/usr/share/xcrysden/Tcl/fs/toolbox.tcl
/usr/share/xcrysden/Tcl/fs/wnFS.tcl
/usr/share/xcrysden/Tcl/fs/wnFSInit.tcl
/usr/share/xcrysden/Tcl/fs/wnReadStruct.tcl