/usr/share/xcircuit/panzoom.tcl is in xcircuit 3.8.78.dfsg-1+b2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 | # panzoom.tcl --- rebinds keys Z and z for a zoom style in which
# the page is centered on the cursor position
# (provded by Ed Casas, 9/4/03)
xcircuit::keybind Z { pan here ; zoom in }
xcircuit::keybind z { pan here ; zoom out }
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