/usr/share/fonts-font-awesome/less/ is in fonts-font-awesome 4.0.0~dfsg-1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/fonts-font-awesome/less/bordered-pulled.less
/usr/share/fonts-font-awesome/less/core.less
/usr/share/fonts-font-awesome/less/extras.less
/usr/share/fonts-font-awesome/less/fixed-width.less
/usr/share/fonts-font-awesome/less/font-awesome.less
/usr/share/fonts-font-awesome/less/icons.less
/usr/share/fonts-font-awesome/less/larger.less
/usr/share/fonts-font-awesome/less/list.less
/usr/share/fonts-font-awesome/less/mixins.less
/usr/share/fonts-font-awesome/less/path.less
/usr/share/fonts-font-awesome/less/rotated-flipped.less
/usr/share/fonts-font-awesome/less/spinning.less
/usr/share/fonts-font-awesome/less/stacked.less
/usr/share/fonts-font-awesome/less/variables.less