/usr/bin/start_webtool is in erlang-webtool 1:18.3-dfsg-1ubuntu3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/bin/../lib/erlang/lib/webtool-0.9.1/priv/bin/start_webtool
/usr/bin/../lib/erlang/lib/webtool-0.9.1/priv/bin/start_webtool