/usr/share/zsh/5.5.1/functions
Edit: /usr/share/zsh/5.5.1/functions/vcs_info_hookadd (450B)
## vim:ft=zsh
## Written by Frank Terbeck
## Distributed under the same BSD-ish license as zsh itself.
emulate -L zsh
setopt extendedglob
if (( ${#argv} < 2 )); then
print 'usage: vcs_info_hookadd '
return 1
fi
local hook func context
local -a old
hook=$1
shift
context=":vcs_info-static_hooks:${hook}"
zstyle -a "${context}" hooks old
zstyle "${context}" hooks "${old[@]}" "$@"
return $?