This plugin is for having info from your mercurial (hg) repo in your prompt
you can enable it by addin "mercurial" (without quotes ) to your plugins in
your .zshrc :

plugins=( ...mercurial...)

You can also costumize the way it looks.

The custom variables are :

For branch name:

ZSH_THEME_HG_PROMPT_PREFIX      This sets what will be shown before the branch name
ZSH_THEME_HG_PROMPT_SUFFIX	This sets what will be shown after the branch name
ZSH_THEME_HG_PROMPT_DIRTY	This sets what will be shown when the repo is dirty 
ZSH_THEME_HG_PROMPT_CLEAN	This sets what will be shown when the repo is clean

For status of repo:

ZSH_THEME_HG_PROMPT_ADDED	This sets what will be shown when a file is added to the repo
ZSH_THEME_HG_PROMPT_MODIFIED	This sets what will be shown when a file is modified
ZSH_THEME_HG_PROMPT_DELETED	This sets what will be shown when a file is deleted  
ZSH_THEME_HG_PROMPT_MISSING	This sets what will be shown when a file is missing (deleted by non-hg command, but still tracked)
ZSH_THEME_HG_PROMPT_UNMERGED	This sets what will be shown when a file is not merged
ZSH_THEME_HG_PROMPT_UNTRACKED	This sets what will be shown when a file is not tracked

For bookmarks:

ZSH_THEME_HG_PROMPT_PREFIX	This sets what will be shown before the bookmark name
ZSH_THEME_HG_PROMPT_SUFFIX	This sets what will be shown after the bookmark name

To configure add this vars in your theme 
Example config:

ZSH_THEME_HG_PROMPT_PREFIX="[%F{yellow}"
ZSH_THEME_HG_PROMPT_SUFFIX="%f]"
ZSH_THEME_HG_PROMPT_DIRTY=" %F{red}*%f"
ZSH_THEME_HG_PROMPT_CLEAN=" %F{green}°%f"

ZSH_THEME_HG_PROMPT_ADDED="%F{green}+%f"
ZSH_THEME_HG_PROMPT_MODIFIED="%F{blue}*%f"
ZSH_THEME_HG_PROMPT_DELETED="%F{red}x%f"
ZSH_THEME_HG_PROMPT_MISSING="%F{magenta}!%f"
ZSH_THEME_HG_PROMPT_UNMERGED="%F{yellow}═%f"
ZSH_THEME_HG_PROMPT_UNTRACKED="%F{cyan}?%f"