/lib/udev/rules.d/99-laptop-mode.rules is in laptop-mode-tools 1.71-2ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 | ACTION=="change", SUBSYSTEM=="power_supply", ENV{POWER_SUPPLY_NAME}=="|AC|ACAD", RUN+="lmt-udev auto"
ACTION=="add|remove", SUBSYSTEM=="machinecheck", RUN+="lmt-udev auto"
ACTION=="add", SUBSYSTEM=="usb", RUN+="lmt-udev force"
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